Severus absently rubbed his arm, where the Dark Mark had been burning as late as last night. Then he turned and took another dose of his Refreshment Draught, which he had needed more and more often lately. He made an absent note to experiment with some less addictive ingredients than the dragongrass that currently drove it. It would not be good to have his eyes suddenly break out into blood when he was in the middle of a class because he had gone too long without a dose.

             So far, the Dark Lord appeared to accept the ridiculous rumors that Albus wanted to spread. He had smiled when Severus first explained the wound to him, and spent some time rubbing his fingers up and down his own arm as if he could feel the pain from a distance and rejoiced in the weakness of his enemy. Then he had abruptly ordered Severus back to the school so that he could speak in private with “other trusted followers.”

             When the Dark Lord trusts someone, Severus thought as he placed the empty vial with the others that the house-elves would clean that day, it will be time to leave Britain as fast as I can, because it will mean he has gone mad and will try to blow up the world next.

            On that front, at least. On the front of the other task that Albus had assigned him…

             Severus shut his eyes and let his mouth work through a final, harsh grimace of distaste. He would not, of course, demonstrate these emotions in front of anyone else. Too many of the other professors were Potter’s fans and thought his reasonable objections to the brat mere prejudice. Albus would peer at him through those half-glasses and speak a few devastating words. Severus Snape did not enjoy suffering, and he had long ago learned to choose the lesser pain of doing what Albus asked over the greater pain of insults from him.

             He did not have to like the boy. He did not have to cherish him in the way that Minerva did and which his colleagues thought him inexplicable for not eagerly employing. He simply had to train him.

             In the training, Severus would break down Potter’s bad habits and rebuild him as someone more obedient, a true student who would do as he was told and follow directions. Severus had no idea why such things were so hard for students, especially when the instructions for a potion were clearly written out on the board. Severus knew he had the clearest handwriting of any professor at Hogwarts. If the little imbeciles could reason out the sprawling tangle of Filius’s hand, they should have little trouble with his.

             He would build him, and bend him into the pattern that their survival of this war required.

             Or he would break him, and show Albus the impossibility of building something worthwhile out of the chaos of shattered pieces that resulted.

             Severus smiled tightly and turned to cast several cleaning charms on his robes. Tonight was the Sorting Feast, and he did not wish his newest Slytherins to see him with dust or drops and dibs of ingredients on him.

             Tonight was also the point at which Albus would make the announcement that Horace was taking over the Potions classes and Severus succeeding to the Defense position. Severus could at least anticipate the students’ immediate reactions with a faint smirk, if not the hard work that would follow during the year.

             Potter’s reaction in particular.

             When Severus left his quarters and strode up to the Great Hall, no one from Albus to Minerva could have faulted the cold neutrality of his face or the swiftness of his stride.

             Nor could any of them have fathomed the private, intense glee that he carried in his heart.

 *

             Draco leaned his chin on his hand as he sat at the Slytherin table and tried to relax. He knew how he was going to accomplish the task the Dark Lord had set him, though he didn’t know how long it might take. He wouldn’t allow himself to worry about that for right now. He deserved internal applause for his good idea.

             Meanwhile, he could watch the new professor at the High Table. The fat, nodding, smiling professor who would probably squeal if you poked him and who hadn’t bothered to invite Draco to the meeting of his “Slug Club,” though he had invited Potter.

             Draco smiled. He couldn’t even be irritated about that, not when he remembered how he had stepped on Potter’s face and broken his nose. He shot a glance across the Hall at the Gryffindor table and made out Potter just now stumbling in, under the guidance of Professor Vector, who’d apparently been assigned to watch for stragglers tonight—and fix broken noses. He laughed quietly, but shook his head when Blaise elbowed him. He would share his source of amusement later, when he had decided whether he wanted to tell his friends that Potter had spied on a private conversation.

             Potter gave him a single, hate-filled glance. Draco straightened his back, some of his worry washing away. There was the reason he had to succeed, right there. The “Light” side hated him and would never accept him. They were far worse than the Dark Lord, who would at least give Draco proper credit for his efforts.

             Then Potter peered more closely at him, frowned, and shook his head. Draco had no idea what he had seen, but it made his shoulders stiffen. If Potter suspected the existence of the Dark Mark he now carried, then things would become worse than insupportable.

             Luckily, Potter’s friends pulled him down into his seat then, and Headmaster Dumbledore stood up and cleared his throat. Draco reluctantly turned to face the ancient idiot, and noticed that Professor Slughorn and Professor Snape were both standing up.

             “May I introduce our new Potions professor,” Dumbledore said, “Professor Horace Slughorn. Though perhaps new isn’t quite the right adjective, as he has taught here before. Some of you might have parents whom he educated.”

             The fat man bobbed his head up and down, his mouth distended and his eyes so bright that Draco suddenly wanted to see what he would look like disappointed, just for the contrast. At least most of the Slytherin table seemed as disgusted as Draco did. The rest of the Great Hall looked relieved, of course. They probably dreamed that they had a chance at good Potions marks now. Draco sniffed. Professor Snape had performed a valuable service as long as he taught Potions. He kept people who had no business learning such a difficult subject from becoming Potions masters and killing someone.

             “And Professor Snape will be serving as our new Defense Against the Dark Arts teacher.”

             Draco had suspected this, and managed to incline his head and look wise as gasps sounded from around him. Potter, meanwhile, was on his feet, his face red, his eyes bulging and fixed on Professor Snape.

             Draco looked eagerly at his Head of House to see how he would respond.

             Professor Snape simply inclined his head slowly so that it looked like the polite nod one duelist would give another, his eyes locked on Potter’s. Potter shook his head furiously and slumped back into his chair, staring at his plate. Dumbledore spoke more words, probably patient and blindly hopeful, but Draco didn’t listen, too busy drinking in Potter’s pain.

             Let’s see him earn those artificially inflated marks in Defense now, with a real and competent professor teaching the class.

             But thoughts of Potter could not occupy him long as his sleeve shifted and he felt the cloth rubbing against the Dark Mark. Draco grimaced and reached for a glass of pumpkin juice that had just appeared. Perhaps he should approach Professor Snape for some help of his own. Not because he wanted to let the man in on his task, of course—the Dark Lord wouldn’t like that—but because what Professor Snape knew about handling Dark magic might prove useful for Draco’s repairing of the Vanishing Cabinet.

 *

             “Can you believe that we’ll still have the greasy git for a teacher?”

             Harry shook his head in disgust at Ron’s remark. “Why couldn’t Dumbledore hire Professor Lupin again, if he couldn’t find anyone else?” he asked, and flopped back on the couch in the Gryffindor common room with his arm over his eyes.

             He hated the feelings churning up and down in his gut. He’d counted on a year that was already going to be hard enough, because he had to make so many changes and live up to so many expectations and take care that his secrets didn’t escape. And now Snape was going to teach the one class Harry had always been comfortable in and make his life that much more difficult.

             “It’s not the end of the world.” Hermione sniffed as she sat on the couch beside them. “Professor Snape probably knows a lot more about Dark magic than Professor Lupin does, to be honest. He could be a brilliant teacher.”

             “Could be, but he won’t,” Ron said. He picked up a pillow and threw it across the room, nearly hitting a first-year. “He’ll sabotage all our efforts and take points from Gryffindor, just you wait and see. And then we’ll fall further behind in learning about Dark magic. And that could be disastrous because we need to fight You-Know-Who.” He lowered his voice on those last words and glanced at Harry’s scar. Harry rolled his eyes. He wondered idly what Ron would say if Harry told him he was less worried about the scar on his forehead than the lower parts of his face, the ones the glamour was covering.

             “Oh, say the name, Ron, for God’s sake.” Hermione tapped her wand against her hand and glared at Ron.

             Ron opened his mouth, and it seemed another argument was going to start, so Harry jumped in. “We’ll have to make sure that he can’t sabotage us too badly,” he said. “What do you say to starting up Dumbledore’s Army again? Unofficially, until we find out how rubbish Snape’s teaching is.” Harry didn’t think he would mind seeing Luna and the other friends he’d made from other Houses at the meetings. Besides, it would give him more time to practice the spells that had been theory only all summer.

             “That’s a wonderful idea, mate!” Ron clapped him on the back. “But don’t worry, his teaching will be rubbish, so we won’t have to wait long.”

             Even Hermione was smiling, though she tried to hide it by hunting for dust on her already clean robes. “That is a good idea, Harry,” she said. “I’ve done some reading about how Transfiguration can be used in battling the Dark Arts, and…”

             Harry relaxed as she chattered on. He was going to survive this. It wasn’t as terrible as it had looked at first.

             Like my stupid heritage. I hate it, but I got used to hiding it, and now it doesn’t bother me as much as it did.

             Mostly, Harry wished his mum was alive so he could talk to her about the story of how she’d—slept with Snape. It made him blush to think about, but it had happened, and it seemed stupid to deny it.

             I can put up with it because no one knows about it. And I can put up with Snape teaching Defense because our real learning is going to happen outside the classroom.

             Not for the first time, Harry smiled at Ron and Hermione and thought how lucky he was to have such great friends.

 *

             Severus wore no smile as he watched his sixth-year students enter the classroom, but he had a hard time fighting one back when he saw the way Potter walked in: striding like a king, his lackeys on either side of him, his head tilted so far back that it was a wonder he could smell anything.

             As expected. His father down to the bones. Anything else is an illusion. Including that fabled skill at Defense.

             Potter took a seat towards the front of the classroom, all the while glaring at Severus without blinking. Severus took exquisite pleasure in returning the stare until such time as Potter finally shuddered and looked down at the desk. Even then, of course, the brat couldn’t admit he’d been beaten and pretended he had only turned his glance away because he needed to find his book.

             Perhaps I shall teach him humility, if nothing else, Severus decided. He looked swiftly over the class and concluded his count of the students. An unusually large number of them had managed to gain high marks on their Defense OWLS. Of course, that was because they hadn’t had a proper teacher in years, and the exam proctors themselves could stand a thorough replacement.

             I shall break them soon enough, he thought, as his gaze settled on Weasley and he watched the red-headed blunderer swallow uneasily.

             “You will learn true spells in class this year,” he announced. The persona he used when he wanted to demonstrate the nature of Potions to students was subtle, insinuating, intriguing; this one he had deliberately chosen to be blunt. He would scrape the withered dreams of several students from the sides of this classroom before the week was out, or know the reason why not. “The nature of Dark magic, and how to counteract it. The nature of Dark creatures, and how to hunt them. The minor hexes and jinxes that you have wielded so far will slide so far down the list of your priorities that you will wonder how you managed to exist knowing only them.”

             He curled his lip and glanced hard at Longbottom, who had managed to earn the necessary mark, perhaps through his grandmother’s bribery of the proctors. At least he had the sense to look intimidated, unlike Potter.

             “I have to remedy the effects of five years’ neglect of this post,” he said coldly, “and I have to do it beginning with you, who have gone through those five years and doubtless are used to thinking of this as a class without work. I would ask pity for my position if I imagined any of you capable of understanding me, and if I needed pity.”

             Longbottom now looked ready to faint. Weasley stared down at his desk, moving his quill back and forth. Granger looked half in awe. In truth, if Granger had not been in Gryffindor, Severus might not have found her so insufferable; he had dealt well enough with several Ravenclaws who expressed a proper admiration for his teaching ability.

             Potter had returned to his glare.

             Why wait? Severus thought suddenly. He had planned to hold off on his demonstration of superiority over Potter, to heighten the class’s fear. But now he saw that that would be counterproductive. Potter had enough of a swagger already, because his previous professors’ incompetence and the dazzled eyes of celebrity-worshippers had permitted him to get away with so much for so long. A delay would only increase his misplaced confidence.

             “Mister Potter,” he said. “You will asset me in a duel.”

             Potter’s glare grew more intense. He rose to his feet without a word and drew his wand. Severus sent him to the far end of the room; the tables, unlike most of those in the Hogwarts classrooms, were arranged in a circle along the walls so as to give an open space suitable for dodging and darting. At least, they were now. Severus wondered in disgust how the others had taught with the classroom as crowded as it had been. He’d had a better opinion of Lupin’s sense than that.

             Severus held his wand high and studied the class slowly. In the middle of appearing as if he would say something to them, he whipped towards Potter and cast his first spell. “Retinnio!”

             The curse whirled towards Potter like a blazing white arrowhead turning end over end. When it hit him, it would make his bones ring as if he were a gong struck with a heavy paddle. Severus knew well enough that none of the Defense books mentioned the counter to this one. He waited contentedly.

             Potter stuck his wand out in front of him like the reaching fingers of a baby and cried, “Protego!”

             Severus would have laughed aloud if his astonishment had permitted him to do so. To use the Shield Charm against the Resounding Curse when it would simply be shivered to shreds—

             The familiar silvery shield appeared in front of Potter and the arrowhead crashed into it. A heavy vibration traveled through the classroom, accompanied by a noise like three dozen cymbals that made Severus’s back teeth ache. The shield dissolved like the still surface of a shaken glass of water.

             But the Resounding Curse was gone, dealt with. And as Potter sprinted to the side and took aim again, Severus realized that that was all Potter had wanted. It didn’t matter to him that he could not create a permanent shield to shelter behind when faced with a spell like that. In fact, perhaps he had even planned on it.

             From a new position, half-crouched under a table where a terrified-looking Hufflepuff girl sat, Potter snarled, “Compes!”

             Severus didn’t see the little snake of light that ran along the floor towards him, so quickly did it move. He knew that was a trait of the spell and not the wizard who cast it, but it was still not pleasant to feel the suddenly conjured shackles appear between his ankles, the chain automatically shortening and jerking him from his feet.

             He did not fall, of course. He could not do such a thing in front of his class and expect to retain any authority. He aimed his wand at the shackles as they formed and, after a non-verbal Balancing Charm that brought him abruptly back upright, cast “Finite Incantatem” aloud, so that he might show his contempt of Potter’s supposed “mastery.”

             The shackles crumbled, but Potter had already scurried to another part of the room—Severus had never realized that he so enjoyed imitating an insect—and chanted another hex. Severus did not hear the incantation this time, but he recognized the effect as it boiled towards him, visible only as a heat shimmer. Potter meant to turn his breath against him, making it into steam that would blind Severus.

             It was a charm that was in the Defense Against the Dark Arts books that had been chosen in the past. Severus knew that. Why he should have been so surprised that Potter had studied it already, he did not know.

             Again, his quick Finite dismissed the hex, and then he moved back on the offensive with a Line of Fire Curse that made dancing flames race across the floor towards Potter. They would not hurt him badly even if they reached him—no more than the hotfoot that Granger had given him in these students’ first year—but they would force him to move constantly and disrupt his concentration.

             Potter yelled two words without pausing for breath. “Aguamenti! Corycus!”

             A blow from an invisible fist hit Severus low in the middle of the back, staggering him. The Line of Fire Curse vanished. Potter ran to a new position, his eyes bright and his hair flapping around him. Severus had seen the same enthusiastic expression before, when Lily was staring into a complicated potion that she had managed to brew right.

             He hated the sudden return of that memory as much as he did the reluctant acknowledgment rising up inside his mind.

             Potter is good at Defense after all.

             Of course, that revelation simply sparked another and more indignant one as he stepped back and said coldly aloud, “That will do for now, Mister Potter.”

             If he can apply this brilliance in one area, then he could apply it in another. Learning complicated spells is not more difficult than following complicated potions instructions. He should have been doing much better in Potions than he did. That he did not implies that he did not wish to concentrate enough.

             Severus considered that a personal insult. It was one thing for Potter to simply be miserable at Potions; it was another thing for Lily Evans’s son to have inherited her talent and refuse to exercise it because he was lazy or busy with other things he considered “more important.” Suddenly Horace’s excited comments the other night about Potter’s performance in his class, which Severus had listened to with half an ear, had taken on a new significance.

             He could do it. He did not wish to.

             He will pay for that.

             He turned away from Potter, because he did not trust his fragile hold on his temper if he had to confront the boy right now, and noticed that the other students were watching with their mouths open and their eyes round. Severus waved his wand, and the air shuddered with the sound of thunder. The watching students jumped and, in the case of Longbottom, squeaked.

             “That was a true duel,” Severus said coldly, “though less deadly than the kind you will fight if you ever deal with a Dark wizard. Now, who can tell me what spells I used in this display? You, Longbottom?”

             That moron’s cowering and spluttering were sweet honey to Severus’s taste after Potter’s confident spells and the flushed, defiant look that Potter threw him before he walked to his seat.

             As was the tiny bit of flavor to be gleaned out of all of this, the fact that he would not have to mentor an utter incompetent. Severus told himself that he could live with his bitterness at having been mistaken because it would mean being spared the worse bitterness of long evenings in the company of someone he could not teach.

 *

             “Potter. Stay behind.”

             Harry lifted his head and waved to Ron and Hermione, who were lingering behind and giving him concerned looks, to go ahead. He knew that Snape was going to assign him a detention or take points for the duel earlier in the class. That was only obvious. Harry had done brilliantly against him, had shown that he wasn’t afraid of him, and that had made Snape’s mouth twist up like he’d swallowed an earwax-flavored bean.

             Snape stood next to his desk now, watching Harry approach. Harry stared at him coolly. It was kind of exhilarating to stand here like this in front of Snape, no matter how much he’d been looking forwards to getting away from him in Potions at last, and know that he was basking in the glow of a successful defeat and hiding an even bigger secret.

             He’d probably claim it’s all down to his genes if he knew about it.

             That made Harry more determined than ever to keep the secret private. He didn’t want to give Snape any pleasure.

             Snape twisted his wand the moment the last student was out the door, and Harry heard the noises from the corridor diminish. He immediately knew it was a variation on a Silencing Charm and wanted to know how it worked, but Snape turned to him and Harry snapped his mouth shut. He was damned if he would ask.

             “You may have heard by now,” Snape said, picking his way through the words like they were shards of glass, “that the Headmaster has been wounded in the fight against the Dark Lord. He will not be able to complete some of the training in Defense that he had intended to complete with you.” His voice grated on the last words and his eyes shifted away from Harry. Probably hates to think about anyone being nice to me, Harry thought cynically. He’d get along great with Uncle Vernon. They could compare notes. “He has asked me to take over that training.”

             Harry stared at him, and waited, and waited. When it became clear this wasn’t a joke, he shook his head and snorted. “Because that worked so well with the Occlumency lessons.”

             “Are you saying that you disrespect the Headmaster’s judgment?” Snape’s voice was soft and eager.

             “When it comes to you and me and you teaching me, Dumbledore doesn’t know what he’s talking about,” Harry said.

             It was the first thing that came to mind, and he knew he should have restrained himself when Snape’s mouth curdled into a smug smile. “Detention tonight at eight-o’clock, Potter,” he said. “Be sure that you bring your wand.” And he turned to gather up papers as if that simple motion could dismiss Harry from existence.

             Harry walked slowly out of the room, taking deep breaths so that he would subdue his inclination to shout and storm about the unfairness of it all.

             When I act on impulse, I get in trouble. It was true in the Department of Mysteries, and it’s true this time. It’s better to practice my lies and prepare for trouble, because that way, I can actually handle it.

             So Snape wants to “train” me? So what? It’ll take up some time, that’s all. My real training is going to come with Dumbledore’s Army. I know that. I’ll make time for that. I’ll work hard at that.

             Harry grinned, then, as a new thought struck him.

            And if he spends the detentions trying to train me instead of making me scrub cauldrons or write lines, I can really frustrate him by just not cooperating. I can show him that there’s no way I’ll accept him as a teacher, and there’s not a bloody thing he can do about it.

            He practically bounced down the corridor to join Ron and Hermione, the thought of how much Snape was going to hate him making him chuckle with glee.

            There’s another advantage, too. The more he hates me, the more he can’t stand the sight of me, the less incentive he has to ask me questions or try and pry into my secrets.

            I can’t wait for tonight.