Chapter Ten: Practice and Theory

Warning: cruelty to animals

Autumn, 1975


Contrary to Professor Slughorn's prediction, Severus found that detention with Madam Pomfrey had nothing to do with the infirmary. It had everything to do with cutting down dead stalks, raking out brown leaves and mucking about with mulch and compost in Madam Pomfrey's physic garden.

It was achy, boring labour, for he had to do it all without magic. ("You could stand to learn something about the care of living things, and you can't do that at wand's length," Madam Pomfrey had said.) Nevertheless, it was better than listening to the histrionic groaning of injured Quidditch players and the self-absorbed whining of students whose spells had backfired on them in class because they hadn't done their homework the night before.

Severus had been in detention since Monday, working from the end of lessons until dusk. It gave him no time for homework until after dinner, and now, on Wednesday night, surrounded by books at a table in the Slytherin common room, he was beginning to worry that he wouldn't be able to keep up.

Everyone else had gone to bed except for Olaus Ruskin and Rabastan Lestrange, who sat at the next table doing their own homework. Soft green light fell on them from the lamp hanging over their heads, giving their skin an odd, pallid cast.

Lestrange yawned hugely, then said, "Vector is such a bitch. Doesn't she know the match with Gryffindor is less than three weeks away? Why is she setting an exam tomorrow?"

"Because that's what teachers do," said Ruskin. "Anyway, you asked for it. You're the one who took N.E.W.T.-level Arithmancy. And what about Bones?" He picked up the parchment he'd been writing on and brandished it in Lestrange's face. "She's assigned us three feet on demonic possession, from prehistoric times to the present. What do you think of that, eh?"

"You asked for it," said Lestrange. "You're the one who took N.E.W.T.-level Defence Against the Dark Arts."

"It'll be useful enough." Ruskin's indolent smile belied the sudden glint in his eyes. The gleam faded in the next moment and the smile broadened into a grin. "Unlike Arithmancy. Why, I ask you, does Arithmancy exist?"

"So you can get your N.E.W.T. in it, get an apprenticeship in Magical Mechanics and go to work in your dad's firm. If," Lestrange sighed, "you have to work for a living."

"If you have to work," said Ruskin. "Wouldn't it just be easier to marry a Black?"

Lestrange frowned resentfully down at his Arithmancy textbook. "They're all taken."

"Mmm," said Ruskin, looking as though he hadn't thought of that before. But Severus imagined that, since his family had been invited to Bellatrix's and Narcissa's weddings, the fact that Andromeda also was married couldn't have escaped him.

His mouth twitching, Ruskin asked, "But doesn't Andromeda have a daughter?"

"She's a half-blood," Lestrange said contemptuously. "And she's two years old," he added, as if that were a far less important fact about Andromeda Tonks's daughter.

Finally Ruskin laughed. "You know what, though, Rabby?" he said then. "You're right about lessons. They interfere with Quidditch practice. We really need to do something about Potter's Chaser's Fade and his Holyhead Double Loop."

"Not to mention Black and his Bludgers," said Lestrange with a grimace of recollected pain.

Severus, having no interest in the conversation beyond the fact that its noise distracted him, flipped through his Charms textbook to the day's homework questions.

"Too bad Severus never made the team. We could use him now."

Severus looked up. Ruskin's eyes danced in amusement.

"I'd like nothing better than to have a good Firewhip at my disposal, to knock Potter off his broom when he gets annoying," said Ruskin.

"Hooch would have you off the team," said Severus shortly. "And Dumbledore might well have you out of the school."

"Some serious Dark magic, is it?" said Ruskin. "I saw the look on Pomfrey's face when she was examining Pettigrew. Is it yours?"

Severus stared at him. "What do you mean?"

"The Firewhip," said Ruskin. "Did you invent it?"

Severus hesitated, trying to decide how to answer, for he rarely knew whom to trust with the truth.

"Of course he did," Lestrange said into the silence. "Look at him."

"Is it really worse than the Breath-taker?" Ruskin asked. "Or better, I should say. Did you have to teach Pomfrey how to finish mending Pettigrew?"

"No, all she needed was the incantation. She worked the rest out for herself."

"So it is yours," said Ruskin.

"Yes," Severus said after a moment.

Ruskin smiled. "Oh, good. You shouldn't have any trouble teaching it to us, then."

Severus looked from one to the other. It occurred to him that nobody else on the Slytherin Quidditch team seemed to think it was necessary to sit up in the common room past ten at night in order to get their homework done.

"Do you really want to learn it?" Severus asked.

"Well, why else would we ask!" said Lestrange.

"I don't know," said Severus. "It's not like you need to defend yourselves. Even Potter wouldn't dare hex the Head Boy and his friends."

"No, he wouldn't." Ruskin leaned back in his chair and looked Severus full in the face. "It's the spell itself that interests me--the power in it. And you, Severus. Who would think you could create spells like Breath-taker and Firewhip? I don't think any other student at Hogwarts could do it, and I really admire you for it."

Severus had no reason to think him insincere. Ruskin was one of the few people who had never taunted him and one of the fewer still who had always come to his defence. That is, when he took enough notice of Severus to see that he needed defending.

Still, Severus found it hard to believe him. "You admire me?"

"I just said so, didn't I?" Ruskin retorted with a laugh. "I've truly never met anyone like you."

He and Lestrange shut their books and came over to Severus's table. Ruskin slid into a seat opposite Severus and Lestrange sat beside Ruskin.

"Come on, Severus," Ruskin said. "Teach us the spell."

Their very attempts to charm him put Severus on his guard. "I taught you Levicorpus, and look what happened. It got out, the whole school knows it, and now every time I turn around, somebody's pointing my arse at the ceiling. Even Pettigrew hit me with it a couple of weeks ago."

"It wasn't us who let the incantation out," said Lestrange. "Aren't you the one who blew up and yelled it at Potter and his gang?"

"Yes, but he might not have been the only one who spoke it aloud," Ruskin said. He ticked names off on his fingers. "Evan Rosier, Douglas Wilkes, Regulus Black, Fordon Avery--we all learned Levicorpus together last year, remember?"

"Oh. Oh, yeah," Lestrange said. "Reckon it could have been one of them, then. I know it wasn't me."

"And I know it wasn't me," said Ruskin. "Funny when you think about it. You have to be damned sharp to learn a spell when you've only heard the incantation a couple of times. Potter's bright, but is he that bright?" Ruskin frowned slightly, then shrugged. "Water under the bridge." He bestowed a glittering smile upon Severus. "We've got a new spell to learn."

"I'm in detention," Severus reminded him.

"We can work around that," said Ruskin. "And it can't last forever, can it?"

"It's for ten days, Madam Pomfrey says." Severus made a face. "Just long enough for me to finish her autumn gardening. But that's all right, actually, if you want to learn Firewhip. I can catch some little animals and birds while I'm in the garden."

"Catch little animals and birds?" said Lestrange. "What's that got to do with anything?"

"To practise casting the spell on them, of course," Severus said. He had done the same with Sectumsempra at home during the summer. "We can't practise on each other, the way we did with Levicorpus. The Firewhip hurts."

"Of course it does," said Ruskin. "You were there on the way back from Hogsmeade, Rabby, you dolt! You remember how Pettigrew squealed."

"Oh...yes," Lestrange said slowly, as if he'd only just comprehended it. He looked at Ruskin. "So you think you'll find it useful?"

Ruskin's lazy smile didn't quite fit in with the diamond-hard glint in his eyes. "I think a spell like the Firewhip can take a chap an awfully long way."

Severus was sure he was missing something. Exactly where did Ruskin expect a Dark burning spell to take him?

"Well, Severus?" said Ruskin.

Ruskin's persistence suggested that not only could he make use of the Firewhip, he needed to make use of it. Why? Severus wondered. There was only one way to find out and only one way to stay in Ruskin's good graces.

"All right," said Severus. "But it will have to wait until I'm out of detention. We can't practise in the Slytherin dungeon after dinner; it's not safe to play around with a spell like Firewhip indoors. Besides, when you reach the point where you'll be casting it on animals..."

"They'll squeal," Ruskin supplied.

"Like Pettigrew," Lestrange elaborated.

"Yes," said Severus. "Right. So..."

"So you finish up your detention with Madam Pomfrey and collect your test subjects," Ruskin said. "Rabby and I will find us a place to play."

****

Although he had at first heartily loathed his detention, by the end of his ten days in Madam Pomfrey's physic garden, Severus was beginning to think it wasn't so bad after all. His muscles had stopped aching, the crisp autumn air invigorated him, and the freshly-turned earth smelled rich and sweet. Moreover, there was a certain tidy progress to be noted, a certain feeling of accomplishment to be enjoyed as he weeded, raked and pulled out old stalks. He even felt oddly tender toward the mostly inoffensive medicinal herbs as he tucked them in for the winter under mounds of straw.

Except for the few minutes each afternoon when Madam Pomfrey came out to check on him, give him instructions and, occasionally, praise his increasingly meticulous work, Severus worked alone. But solitude in the garden was not the same as solitude in his bedroom at home, or in the dormitory or library at school. What he felt in the garden, he eventually came to understand, was not loneliness but calm.

It certainly didn't ruffle that calm to know that here, under Madam Pomfrey's protection, his enemies couldn't touch him. Today he even knew exactly where they were. Gryffindor had booked the Quidditch pitch for practice, so two of those tiny figures silhouetted against the bright blue sky had to be Potter and Black.

Severus straightened, stretched and, for a few minutes, watched the Gryffindors loop and soar. Then he went up to the hospital wing to get a glass of water. As he drank, he looked around for Madam Pomfrey and presently saw her in her office, far from any windows, scribbling notes on a patient's parchment, with several more parchments piled up at her elbow.

Severus was careful not to disturb her. He finished his water and went quietly back to the physic garden. There he found and put body-binds on a starling and a vole. He stowed them in an enlarged, protective space he'd magicked inside his book bag, alongside a rabbit he had Petrified when he'd found it nibbling on the grass at dawn.

Severus returned the bag to its place on a stone bench. Then, the gentle autumn sun warming his back and neck, he went back to digging compost into Madam Pomfrey's raised beds.

****

"We'll do it here," Ruskin said the next morning.

Severus halted beside him and Lestrange in the shade at the edge of the Forbidden Forest. They were in sight of the Whomping Willow, but at a distance which made it look no bigger than a shrub. Even further away, the turrets of Hogwarts Castle thrust jaggedly into the sky, against a backdrop of scudding grey clouds.

"I'm not afraid of this place, even if everyone else is," Ruskin said, looking into the forest's lightless depths. "I could look after all three of us in there, if I had to."

"Good, because I don't fancy casting this spell in a popular place," said Lestrange. "Though I don't think we need to go into the forest," he added hurriedly. "Do we, Severus?"

"No, this is fine. We'd have trouble seeing what we were doing in there," said Severus.

"Quite," said Ruskin. "And though we may not want to be seen, we certainly do need to see." He was looking some five yards ahead of them, at the Petrified starling which Severus had laid on the grass.

Severus took out his wand. "The incantation for the Firewhip curse is Flammaflagrum," he said to Ruskin and Lestrange. "And when you cast it, you have to want--no matter what--to burn." He looked at the starling. It was Petrified, but of course it still breathed. Its chest rose and fell with rapid bird respirations.

"Well, it's that way with every curse that's worth anything, isn't it?" asked Ruskin. "You have to have the power to do it. And you have to really want to do it."

Though he'd been casting curses since childhood, Severus had never heard it put so succinctly.

"Short and sweet, eh?" Ruskin said, smiling. "But don't credit me. Professor Dumbledore said it first."

More Magical Theory, Severus supposed. He'd have to take that class next year.

"Well, then," he said. "I don't have that many animals to waste on demonstrations, so watch closely."

Severus drew his wand and aimed it at the starling. But he didn't cast the spell at once, for he had to take a moment to order his mind.

He waited until he had before him not the physical sight of the starling's bulging eyes or its rapidly heaving breast, but the vision of his mind's eye: the Firewhip writhing across the starling's body, shrivelling feathers and burning skin.

He was ready. "Flammaflagrum!" Severus said.

The silver lash sprang from Severus's wand and struck the starling. A little puff of smoke rose from its body. When the smoke cleared, Severus saw that his vision had become reality. The starling's feathers were singed and in patches burnt off, with the exposed skin red and blistered, just as Peter Pettigrew's had been.

The bird neither squawked nor moved, however, for the Body-Bind Curse still held.

Severus lowered his wand and looked around. Ruskin and Lestrange were both staring at him.

"Very nice work, Severus," said Ruskin. He pointed his wand at the starling. "Let me give it a try."

"No! Not before I counter the curse," said Severus.

Ruskin looked at him and then, with a mild shrug, lowered his wand. Severus went to kneel beside the starling. He wasn't quite right, he saw, to believe its body was completely still. He could see the bird's tiny heart jittering beneath its skin, like a hazelnut come suddenly to maddened life.

Severus's throat constricted for a few seconds. Then he took a breath and cleared his mind.

Now he saw in his mind's eye the complex, glittering spirals of Madam Pomfrey's Refrigeratus swirling out of his wand, flowing over the starling's body and melting into its skin. He saw the bird's skin heal and its fluttering heart calm into a quiet and regular beat.

"Refrigeratus," muttered Severus, tracing spirals with the tip of his wand over the starling's burns. The crystalline spell flowing from his wand healed the bird's skin. Another pass of his wand restored its feathers.

Severus looked into the starling's unblinking black eye for a moment. Then, wordlessly, he released it from the Body-Bind Curse. The bird shot upward, flying away from Severus as fast as he had ever seen any bird fly. Within moments it looked like a black Snitch, little more than a whir of wings against the sky.

"Oy, there!" said Lestrange. "Why'd you let the bird go? What are we supposed to practise on?"

"Leave him alone," Ruskin said sharply, while looking at Severus. "He has his own practising to do."

Lestrange looked nettled, but said nothing. "Don't worry, I've got another animal in my bag," Severus said to him. He pulled out the vole and laid it on the ground. "Go ahead, Olaus," he said.

Ruskin's eyes took on a distant, icy look. He cast the Firewhip nonverbally and perfectly.

Severus knelt beside the vole. It was burned as the starling had been burned. "Very good."

Severus looked up just in time to see the animation return to Ruskin's face in the form of a satisfied smile. "Thanks. Your turn, Rabby."

"Well, not yet. Unless you want me to hit Severus."

Severus was healing the vole. When the last of its burns were gone, he released it from the Body-Bind. The vole scampered off and disappeared in the tall, untended grass near the edge of the Forbidden Forest.

Severus took the Petrified rabbit from his bag and set it on the ground. "Now it's your turn," he said to Lestrange.

Lestrange was far from dim, but he was no Olaus Ruskin. His first Firewhip curled back around his wand and, barely missing his hand, singed the sleeve of his robe. The second was a ball of silvery flames that popped from his wand and fell straight to the ground, igniting the grass dangerously close to his feet.

Severus doused the fire with an Aguamenti Charm while Ruskin tried without success to stifle his laughter. "Good lord, Rabby! If you don't attract the attention of somebody on the grounds, you'll catch the eye of something inside the forest!"

Worrying about exactly that, Severus looked toward the school. The cold wind and lowering clouds seemed to be keeping casual strollers off the lawns. He peered into the forest's shadows. Nothing peered back. And, except for the distant cawing of crows, the wilderness was silent.

"So what do I do?" said Lestrange, looking frustrated.

"It's best if you see yourself, in your mind's eye, making the spell happen," said Severus. "It's like Olaus said: you have to want to burn the rabbit." He hesitated, then added, "You can't care whether you're hurting it or not."

"Makes it a good spell for enemies, eh?" Ruskin put in. "Since you want to hurt them."

Perhaps it was what Ruskin said, or perhaps it was the look on his face that brought Potter immediately to Severus's mind. Potter, upending him by the lake last spring, so that the whole school, including Evans, could see his underwear. Potter, hanging him up again to take his underwear off after Evans and her friends had left...

"Yeah," Lestrange said, looking as though things had finally fallen into place. "I can get behind that."

He raised his wand and glared fiercely at the Petrified rabbit, making Severus hope that the enemy Lestrange was visualising wasn't him.

"Flammaflagrum!" said Lestrange.

A brilliant Firewhip shot out of his wand, straight for the rabbit, and in the next moment the aroma of roast meat rose to Severus's nostrils.

Severus hurried to kneel beside the rabbit. Its burns, he immediately saw, were worse than those of the starling and the vole. There was almost no part of its body which remained untouched. Even its ears were burned.

It should have died, Severus thought. The Firewhip had burned away most of its fur, leaving huge swaths of raw, red skin. In some places, the skin was crisped black. The rabbit lived, however, for it could breathe. The Firewhip had spared its nose and mouth, so that it drew, with twitchy, shallow breaths, just enough air into its lungs to keep it alive.

The spell's lash had also missed the rabbit's eyes. Glassy and filmed with pain, those eyes were fixed on Severus.

At a loss, he stared back. He did not know how he could repair that much damage, even with Madam Pomfrey's version of Refrigeratus. He didn't think Madam Pomfrey herself could heal those burns.

But without healing the rabbit would certainly die. Severus did not know how long the dying would take. He did not know why that mattered to him. But it did matter, so he pointed his wand at the rabbit's throat. He emptied his mind. He allowed to grow in those voided spaces, like the unfolding of a flower, nothing but the desire to cut. Then he whispered, "Sectumsempra!"

The spell sliced the rabbit's windpipe in half. A bit of blood welled around the wound, and then the rabbit's head fell back. It was dead.

"A new spell, Severus?" said Ruskin's soft voice above him.

Severus turned and looked up. Ruskin was standing just behind him.

Severus rose. "The rabbit's dead. We ought to bury it."

"Why don't you just throw it into the forest?" said Lestrange, coming up to them. He looked down at the rabbit and gave a low whistle. "I do good work, don't I?"

"Teachers go into the forest," Severus said.

"I doubt one would make it in there before something-or-other took care of the evidence," Ruskin said. "But if you want to bury it, then bury it we will." With a flick of his wand, he excavated a hole near the undergrowth at the edge of the Forbidden Forest. He Levitated the rabbit into the hole and covered it up. A few waves of his wand tamped the dirt down, so that it looked as though it had never been disturbed.

"There we are!" said Ruskin. "Lesson's over. I'm ready for lunch." He turned and, with his usual long, loping stride, headed for the castle.

Lestrange went with him, but Severus hung back for a moment. He Vanished the grass burned by Lestrange's ball of fire. He Summoned a few rocks he could see just inside the forest and arranged them over the bare patch so that they looked like a natural jumble. Then he followed Ruskin and Lestrange back to Hogwarts Castle.

****

Severus decided, after their first lesson, that he didn't need to risk being seen teaching Ruskin and Lestrange the Firewhip any longer. Besides, detention had left him with so much homework, he didn't have the time. He told Ruskin and Lestrange that they'd shown enough comprehension of the Firewhip to perfect it on their own and allowed his looming pile of unfinished work to push the spell out of his mind.

He was in a deserted corner of the library a few evenings later, driving himself to finish an overdue Transfiguration essay for which Professor McGonagall was not likely to give him another extension. He was so deep in his work that he didn't know Ruskin was there until a book bag dropped with a thud on the table in front of him.

Severus started and looked up. "Olaus."

"Hullo, Severus. Mind if I sit down?"

Ruskin did so without waiting for Severus's permission, but Severus didn't mind. Maybe Ruskin could help him with his essay.

"Who discovered the Third Law of Transfigurational Limits?" Severus asked.

"Alberuni, sorcerer to the Sultan Mahmud, in 1020," said Ruskin. "And funny you should ask."

"Why?" said Severus.

Ruskin tipped his chair back and peered around a bookcase. Leaning forward and following his gaze, Severus saw Madam Pince at her desk, flipping through filing cards and making notes on a parchment.

Ruskin lowered the front legs of his chair very quietly back to the floor. "Nobody in the library but Pince, and she's not paying any attention to us. But I'd still cast a Muffliato if I were you."

"Why?" Severus repeated.

"Because, one, you're better at it than I am, and, two, I don't want anybody to hear us."

Severus put down his pen and took out his wand. After he had cast the spell, Ruskin leaned back to peer at Madam Pince.

"Good," he said, sitting straight again. "Looks like she doesn't suspect a thing."

"So what is it you don't want her to suspect?" said Severus.

"That I'm going to talk about limits." When Severus blinked at him, Ruskin added, "Not of Transfiguration, but of the Firewhip. It's a very limited spell, you know."

Severus wouldn't have guessed it. "I'm sorry I failed to please," he said coldly.

Ruskin laughed. "Oh, no, sorry!--not the right word--I mean delimited, I suppose. The Firewhip's not as Dark a spell as you'd think, because it's delimited."

"Delimited? What does that mean?"

"You know something?" said Ruskin musingly, his mirth fading to a small smile. "If Dumbledore knew what use I'd make of Magical Theory, he'd never have let me in the class. The term 'delimited' is usually applied to Dark magic, though Dumbledore says there's no reason you can't apply it to Light magic as well. A delimited curse is one which--theoretically, anyway--can do only so much harm. Dumbledore says it's contained by its own nature, or by the boundaries the wizard opposing it is able to place upon it. Or both."

"Both?" said Severus.

"Sure, a lot of curses are like that, aren't they? Take Levicorpus. A wizard can place limits on it. He can counter it by casting Liberacorpus. But it's also limited in itself. If you wait long enough, it'll just wear off."

"Well, I wouldn't call Levicorpus very Dark."

"Right!" Ruskin's small smile grew larger. "Now you're getting it. Because the really Dark curses aren't limited, are they?"

Severus waited, looking at him curiously, and listening, in the otherwise silent library, to the patter of rain on the windows.

"Take your Unforgivables, some of the Darkest magic we know," said Ruskin. "Take the Imperius Curse. Maybe you can dodge it, but I've never heard of anybody Shielding against it. And there's no counter to it. If somebody hits you with an Imperius Curse, it's no use going for your wand, might do more harm than good, in fact. It's what's inside you that counts then. It's your will against the caster's power, full stop, end of story. Same with the Cruciatus Curse. There's no getting away from the Cruciatus Curse, once one lands on you. And no limit on how bad it can get. Nothing to hold it back but the limit nature puts on the caster's power and the limit the caster wants to put on his desire to send you to hell...."

Ruskin fell silent and the rain fell harder.

"Then there's Avada Kedavra," he resumed after a moment. "I mean to say, how do you define the limits on death? Once you get past the heart-stopped-no-breathing part, do we even know what it is?"

"What are you getting at?" said Severus.

"The Firewhip," said Ruskin, leaning forward on his elbows. "It's a delimited curse. You've invented a counter-curse, a piece of Light magic that gives it a boundary. How about that curse you cut Rabby's bunny's throat with? Do you have a counter to that?"

"No."

"Have you been trying to create one?"

"Yes. But it's not as easy as you'd think," said Severus.

"No. It's not easy to limit a spell that can kill if you'll just give it its head. It's like it develops a mind of its own."

"Sectumsempra was never meant to kill," Severus said quickly.

"Ah, but you did kill with it, didn't you?" said Ruskin.

Severus stared at him. He remembered emptying his mind of the rabbit's burned fur, blistered skin and glassy-eyed agony. He remembered permitting himself nothing but the desire to cut, in a place where cutting was certain to end life.

"See what I mean? There's no limit to it. Unless you can place one. But like you said, sometimes that's not so easy to do. It's like some spells just don't want to be hemmed in." Ruskin paused. "So that's what you call it? Sectumsempra?"

"Yes."

"I want to learn Sectumsempra."

"Why?"

"Well, you remember what I said about the Firewhip, that it was a spell that could take a chap a long way? I think Sectumsempra could take me even further."

This time Severus asked the obvious question aloud. "Where do you want to go?"

"Let's just say I have a job prospect. I want to add Firewhip and Sectumsempra to my portfolio."

Suspicion stirred in Severus. "You said Slughorn was giving you a line into the Department of Magical Games and Sports. You won't need the Firewhip and Sectumsempra there."

"Oh, that. That's just the day job." Waving a hand, Ruskin leaned back, his whole body looking fluidly relaxed. "I'm looking for real work. Work proper to a Slytherin." He folded his arms loosely across his chest. Yet as he spoke, he fixed Severus with an unwavering gaze.

"...Most of the witches and wizards who have been revealed as Death Eaters are Slytherin alumni," Slughorn had told Severus. "You're not thinking of--" he began.

Ruskin silenced him with a gesture. "You don't know what I'm thinking of, because I haven't told you. And I won't."

Severus felt his jaw go slack. Questions sprang to his mind. Did Olaus Ruskin want to become a Death Eater? Or was he one already?

"You--you could be putting yourself in a lot of danger," Severus stammered at last.

"Not if we never mention it again," said Ruskin. In their dim corner of the library, beneath the window streaming with icy rain and black with the night, his eyes looked very dark. "I know I won't." He smiled slowly. "And if you did, who'd believe you?"

"If anybody believed me, you'd go to Azkaban. Do you think I want that?"

"Of course not," Ruskin said soothingly. "You're my friend, and I'm yours. You'll teach me Sectumsempra, and I'll get to a place where I can do my friends some good." He straightened and, even though the Muffliato spell was still in effect, lowered his voice. "The world's changing, Severus. Doesn't seem like it here at Hogwarts, where Dumbledore's Head, but it is. Dumbledore's afraid of change. So are the Ministry. They can't cope. They're going to fall. When they do, then...then I'll be one of the ones in charge."

Severus, still staring at him, said nothing.

Ruskin cocked his head. "Of course, you may see reason before then," he said thoughtfully. "I think you've got it in you."

Severus did not care to reply to that. But he did think it best, on the whole, to make sure he kept Ruskin as a friend. "All right, I'll teach you Sectumsempra," he said. "But what I did to Lestrange's rabbit is the most I've ever done with it, so I don't know that it's all that powerful a spell."

"Oh, yes, you do," Ruskin replied. "You created it."

****

Severus Stunned the hedgehog that Ruskin had laid open, so that it would not have to feel its life leaking away.

"There's no boundary to it," Ruskin muttered as he watched the hedgehog bleed. "That's the difference between Firewhip and Sectumsempra. Between the Light and the Dark. Between the owl sleeping in her cage in a patch of sunlight and the owl flying free on the hunt, into the starry, limitless night."

It wasn't the sort of thing Ruskin usually said. It wasn't the sort of thing anybody in Severus's experience ever said, except maybe Dumbledore. But, having cast Sectumsempra many times now in the course of teaching the spell to Ruskin, Severus understood what Ruskin meant. Freedom. There was a certain freedom in not knowing exactly how much a spell you had invented could do, in not knowing exactly how far you could go.

"You don't need me any more," Severus told Ruskin. "I've taught you all I know about Sectumsempra."

"But we're still friends," Ruskin assured him.

****

Ruskin proved it, too. He mustered a group--himself, Lestrange, Rosier, Avery and Wilkes--that seemed to appear every time Potter and his gang started on Severus. He was as good as Severus had ever been at goading Potter and Black into losing their tempers. Better yet, as Head Boy, he could then turn around and put them in detention.

But even Ruskin's conduct, Severus soon came to realise, did not annoy Potter as much as Lily Evans's did.

Severus made the discovery, as he had made some of his earlier discoveries about Evans, in Potions class. Evans had continued to partner him through the autumn term, and Severus had seen that, no matter how much Potter tried to hide it, he truly hated for her to do that.

Severus had reckoned that Potter's initial anger at her would simmer down to the level of bullying pranks, but he was wrong. Potter stayed at the same height of flustered fury which had made him glare at Lily Evans the whole time he should have been brewing his Antisomnia Infusion that first lesson of the term. In several lessons after that, Potter had tried to get Evans to partner with him, probably expecting her to come cringing back like the rest of the Gryffindor curs.

But Evans didn't cringe. Nor did she accept Potter's invitations. She told him bluntly that, since she was there to learn something, she preferred to partner with somebody who took an interest in the class and who, therefore, at least half knew what he was doing.

Evans had paid that compliment to Severus, and yet it wasn't as though she liked him. Oh, they worked well enough together--at least, they did not irritate each other as much as they had at first, and their brews continued to earn top marks from Professor Slughorn--but outside of Potions they had nothing to do with each other. Why should they have done? They had nothing else in common, and Evans was a popular girl, busy with her own friends.

Severus was only grateful that she didn't try to work up some sort of spurious camaraderie with him. He did not generally care for the attention of the popular. They either taunted him, like Potter, or patronised him, as Lucius Malfoy and Narcissa Black had done while they were still at school, expecting him to adore them in return for their desultorily-tossed crumbs of attention.

Severus and Evans, on the other hand, used each other, frankly and unashamedly, in the pursuit of a specific goal: top marks in N.E.W.T.s Potions. They didn't like each other. They didn't have to like each other, as long as they treated each other with respect while they were working together.

It was like Severus's relationship with Olaus Ruskin. Ruskin had used Severus to learn a couple of spells he hoped would gain him the employment that neither of them was supposed to mention. The only difference was that Severus rather liked Ruskin, or, at least, was grateful to him for backing him up against Potter.

That was where things stood in the third week of November, as Severus waited in the Potions classroom for the lesson to begin. As always, to prevent unpleasant surprises, he ascertained the enemy's whereabouts. Potter was in his favourite place near the back of the classroom, sitting at a table with Black and Pettigrew.

Lupin wasn't with them. Apparently his mother was ill again, for he had never missed Potions that term for any other reason. Indeed, when Severus came to think about it, Lupin's attendance hadn't been all that bad lately. He hadn't missed a class since a week before Severus had struck Pettigrew with the Firewhip--

"What are you looking at, Snivellus?"

Potter didn't mock or taunt. He snarled. Severus half-turned in his seat so that he could stare directly at Potter.

"I'll look at any freak show I please," Severus said. "What business is it of yours?"

"You'll look at it from eyes in the back of your head, then," said Black. He drew his wand from the folds of his sleeve and half-surreptitiously aimed it at Severus. "Once I rearrange your face to put them there."

Pettigrew snorted with laughter. "Won't make him look any worse than he does now!"

Potter leaned forward on his elbows and grinned maliciously at Severus. "Know something, Peter? Truer words were never spoken."

The classroom door opened as Potter spoke and Evans walked in. She stopped in her tracks and took in the situation at a glance.

"Leave him alone, Potter."

Evans's face was hard, and her voice, though quiet, sounded somehow more dangerous. But they were the same words she had said by the lake last June, and Severus, when he heard them, felt the same hot flush climbing into his face.

Potter, however, did not act as he had then. He straightened. The grin was gone. He looked at Evans with a quietly earnest expression on his face, like nothing Severus had ever seen there before.

"I will if you'll go out with me," said Potter. "Go out with me, and I promise I'll never lay a wand on him again."

Evans stared at Potter. For the briefest of moments, a fervently longing look flickered through her eyes, a look so rapidly replaced by anger that Severus was never sure afterwards that he'd actually seen it.

"You haven't changed a bit since last year, Potter," Evans said coldly. "So my answer hasn't changed, either. I wouldn't go out with you if it was a choice between you and the giant squid." She turned on her heel and strode to Severus's table. Throwing her book bag on the floor, she sat down next to him.

Severus looked at her curiously. Evans had never chosen to sit next to him before. Ordinarily, she never joined him unless Slughorn called on the class to pair off.

Evans did not look at Severus. Professor Slughorn came in then, followed by a few stragglers. When the students were settled in their seats, he assigned the Draught of Living Death.

Severus had had the sense, after his first Potions lesson, to go through Borage and correct whatever recipes needed correcting. Fortunately, he hadn't come across any recipe since the Antisomnia Infusion which necessitated his asking Slughorn for ingredients from his private stores. Severus didn't know but what, if that occasion arose again, he wouldn't risk brewing his potion inefficiently, or even incorrectly.

Luckily, the Draught of Living Death did not present Severus with that dilemma. All the ingredients he needed to make the potion were available in the classroom storage cupboard. Before long he was half finished. His potion was smooth, blackcurrant-purple and had achieved a gentle, rolling simmer.

Evans, stony-faced and silent throughout the preparation of her potion, had reached the same point. Severus looked over at Potter. His potion was lime-green. From time to time, it gave a bubbling hiss and spurted over the side of his cauldron. The potion was unsalvageable, if Severus was any judge. Potter would have to throw it out and start again.

But Potter didn't appear to notice the mess he'd made. He was looking straight ahead, past Slughorn, who was dousing the flames shooting from Alice Aylsworth's cauldron. Potter stared at the blackboard without seeming to see it, and a muscle twitched in his jaw.

Black looked at Potter and, sighing, gave a little shrug. Only Pettigrew, with a furtive glance, met Severus's eyes.

Finally it dawned on Severus, and as it did so, he wondered how he could have been so blind. Potter didn't hate Evans. She wasn't his enemy. He liked her as much as he had last year. He'd just tried to get her to go out with him, hadn't he?

The only difference was this. Instead of treating Severus with contempt, as she had done last year by the lake, as was the prerequisite for acceptance into Potter's circle, Evans now treated Severus with respect.

That was what infuriated Potter. Lily Evans, a Gryffindor and therefore one of Potter's subjects, Lily Evans, a girl Potter fancied, had the gall to treat Severus Snape like a human being. Not only that, she seemed to be insisting that if Potter wanted her favour, he'd better do the same.

Severus looked at Evans, who was counting out her sopophorous beans. He looked at Potter, who stared at the blackboard while his fluorescent green potion boiled over the sides of his cauldron. The muscle still worked in Potter's jaw.

Severus looked at Potter thoughtfully for another moment, then, returning to his own potion, spread his sopophorous beans out on the table. As he was digging his silver knife out of his bag, he happened to glance over at Evans. In compliance with Borage's instructions, she was cutting up her sopophorous beans.

Severus thought for a moment. Then, adopting the mildest tone he could manage (which took another moment's preparation), he said, "Lily, if you crush the beans, you'll get a lot more juice."

"Hmm?" she said distractedly, looking up.

Severus crushed his sopophorous beans with the flat of his silver dagger. "You see?"

Evans's eyes widened. "Wow," she said, comparing Severus's beans with the beans she had cut. "Look at all that juice!" She imitated him at once, crushing the rest of her beans with the flat of her own knife. Then she slid the prepared beans into her potion.

Severus had done the same. Both their potions immediately lightened to lilac.

"Wow," Evans said again. Then, glancing around the dungeon at everyone else's potion, she added, "Hey, look, we're way ahead of everybody else. Obviously the book's wrong again. Got any other tips?" she asked, peering over Severus's shoulder at his textbook.

"One clockwise stir after every seventh anticlockwise stir," said Severus.

They stirred in accordance with Severus's instructions, and their potions lightened further.

Now was the time. "You and Potter," Severus ventured, "you were saying almost the same things you said when--well, at the lake last year, when I was there."

The pleased look that had lit up Evans's face as she'd viewed her potion's progress changed instantly to annoyance. "You noticed. I suppose I shouldn't be surprised." Her face turned red, and not only from the potion's steam, Severus reckoned.

"Look," said Severus. "I've been thinking. I want to apologise for...." A pang of real guilt, brief but sharp, took him by surprise. "Well...I--I called you a name then. I'm sorry."

Evans stopped dead and stared at him.

"Don't forget your clockwise stir," Severus said.

"Oh, right," Evans said and stirred without taking her eyes off him. "Thank you."

Severus shrugged and returned his attention to his Draught, which was now a clear, pale pink. Out of the corner of his eye, he saw Evans glance at Potter. Then he felt her gaze on him again.

"I mean it." Evans's voice was low and it trembled slightly. "I want to thank you for choosing not to be a bloody stupid prat."

Severus looked up into Evans's pale, tense face.

"You're welcome," he said with a smile.