Severus stomped through Hogwarts castle in a fierce swirl of robes. His school robes were close enough to his habitual black that he could almost believe nothing had changed, but the depth of his black mood told him everything had changed. All because of Albus's stupid, insane, sugar-fuelled ideas. And there was nothing he could do to relieve his desperate anger.

He wanted to stride through the corridors yelling at errant students and taking points, and it was hard sometimes to remember that he couldn't. And other times, stumbling in his gangly, unfitting body, it was impossible to forget. A trio of girls were passing as he tripped over his own feet, catching himself on the stone wall, and they giggled at him. He glared. It didn't matter that physically he was only seventeen, he'd still had nearly two score years of perfecting his glare. They fell silent and scuttled away. It didn't make him feel better.

He should have gone to the Antipodes. He should have gone to Alaska. He should have done anything but stay here in Britain and agree to Albus's ridiculous plan. But he'd wanted to live. He'd wanted to stop looking over his shoulder, stop fearing every stranger and driving away every acquaintance, stop carrying the world on his shoulders. He'd wanted to live, so badly he would have agreed to almost anything to be able to do so. Even this. Even now, as he snarled and scowled and fought the urge to hex everyone around him, he knew he would make the same decision again. This was bad, but the alternative was worse.

So he'd let Albus de-age him, turn him from a grumpy and bitter thirty-eight-year-old into a grumpy and angry seventeen-year-old. It was the only way to escape Azkaban after the end of the war, the only way to escape the retribution wreaked upon the Death Eaters by the world they had terrorised. Only if he no longer existed in the eyes of the magical world would he be safe. So he'd escaped into anonymity and he'd regained the youth he'd never enjoyed the first time around and would certainly not enjoy a second time.

He paid no attention to his surroundings as he stomped fiercely along, trying to bury anger and uncertainty in physical exertion, striding out his old patrol routes as if he still held the power of detention and house points. And since he wasn't used to having to give way to students, was used to having them scuttle aside, he didn't notice the three students approach him until he nearly walked into Draco Malfoy.

Stopping abruptly to avoid a collision, he opened his mouth to snap at them— Then he looked the other boy (the other boy) in the eye and remembered where he was, who he was, and shut his mouth. Malfoy smiled, with a lot of teeth and not a lot of friendliness. "Hello, Snape. I've been meaning to have a little talk with you."

"I have nothing to say to you," Severus said irritably, trying to pass. But Malfoy stepped into his path and Crabbe and Goyle drifted to either side, not enough to be actually threatening – so he would look like a complete coward if he tried to run – but flanking him enough to be worrying. Severus's hand shifted subtly to where he could easily access his wand, more an automatic response to an uncertain situation than a real belief in danger.

He watched Malfoy narrowly. He'd never liked the brat, but to propitiate Lucius and maintain his place in the Death Eater ranks he'd carefully never crossed the younger Malfoy. But now he stood eye to eye with the brat and suddenly Malfoy wasn't a brat but an equal. Severus no longer held the upper hand. And for all he'd looked the other way whenever Malfoy was involved, he'd never taken seriously any accusations against him because Malfoy had always been just the brat and he'd assumed the complaints of the other teachers and students were merely a part of the persecution his Slytherins had always suffered under. He'd forgotten somehow – how? how could he have forgotten? – what it was like not to tower over most of his acquaintance.

"I've been watching you, Snape." Severus shuddered. When had childish arrogance become genuine threat, when had the brat grown up to become a real menace? "You think you're better than us. Strutting around the castle as if you own it, looking down your nose at us. It's time you learn your place, Snape."

Severus's wand was in his hand in an instant, his instincts on high alert, but it was impossible to watch all three of them at once because they were too separated. How long ago had they perfected this technique and how had he failed to notice? Though he gripped his wand firmly he was uneasily aware that his magic had yet to settle into this new body and was unreliable. He'd defied Dark Lords and Death Eaters without flinching but here facing three teenagers he was really and genuinely scared. He was outnumbered and no longer held the security of being the professor, of being the adult. He tensed, ready to fight and sure he'd lose. He'd played out these scenes too many times before in his first youth, though at least this time there were only three instead of four. If he was lucky that would make it less painful. He had a feeling he wasn't that lucky.

"Three against one, Malfoy?" drawled a new voice, drawing all eyes. "Feeling brave today, are you?"

For half a breath the old panic welled up – James Potter, come to join in the fun. Then reality reasserted itself, Severus's vision cleared, and it was a different boy standing there and a different script playing out.

Harry Potter, vanquisher of Voldemort, leant casually against the wall, his wand held idly in one hand as he used it to scratch behind his ear. He could have been talking to a group of friends – but when Crabbe moved, the wand was instantly pointed at him. Potter's stance was still completely casual but the wand was unwavering and there was something dangerous in the electric eyes that couldn't be masked by the lazy droop of eyelids over them or the bored expression. This was not the eleven-year-old boy who'd come to Hogwarts, wide-eyed and bewildered. This was not the fifteen-year-old buried under teenage angst and overwhelming expectations. This was the young man who had faced his destiny and won, grown up now. In control.

Unlike Severus, torn between relief at being rescued and humiliation at having to be rescued. All buried under resentment that Potter could do what he couldn't and self-loathing at what he had been reduced to.

"We were just talking, Potter," Malfoy said defiantly, but the very fact of his defiance was submission.

"Really?" One word, but it held them all in place.

Severus remembered Potter at his trial, standing slouched, hands in his pockets, looking nothing like a conqueror yet in control of the room, forcing the Wizengamot to listen to his unwanted words. "Professor Snape always hated me. But he saved my life over and over. He's not a nice man. But he's a good man." But not even Potter could control the whole wizarding world: any Death Eater was to be done away with, Potter's word or no. And then Albus Dumbledore's hare-brained plan had put Severus back at school in Malfoy's clutches. It had been the only way to survive and Severus had been grimly determined to live. This, though, was not what he had in mind.

Malfoy and Potter faced off, a battle of wills taking place in the space where their gazes met, but there was never a doubt who would win, even when he was lounging against the wall looking amused. Potter might not be able to control the world, but he could easily control three seventh years. Severus looked between them, knowing himself the prize at stake and hating it, painfully aware that Potter knew who he really was. This would be a perfect opportunity for the boy to extract payment for years of harsh treatment which at the time had seemed necessary to keep the boy from getting too self-important but now felt like a suicidal attempt to alienate someone whose goodwill could save his life.

"Wasn't really interested anyway," Malfoy sneered, tearing his eyes away and trying to convey through cockiness that it had been his own idea, not a surrender. No one was fooled, but Malfoy and his goons slunk away without backward glances in search of an easier target.

Leaving Severus, mortified to be helped by Potter. And bewildered that he had been rescued by a Potter, instead of needing to be rescued from a Potter. Unwillingly but refusing to submit as Malfoy had, he met Potter's eyes. Funny how the young man looked different when they were the same height.

"You okay?"

"I don't need your pity, Potter," he snapped.

Potter was unruffled. "I wasn't offering it."

"I don't need your help either."

He shrugged, unconcerned. "Sorry. Next time I'll let them hex you into a pulp."

Severus managed to swallow down his spleen with an effort. This was the boy who'd defeated Voldemort single-handed, who could control the Malfoy brat where he couldn't. It wasn't wise to annoy him, and Severus very much wanted to live.

More than that, though, Potter knew who he really was. Potter, Albus, and Minerva all knew because they'd been the three with the power to turn him into this travesty of what he had once been. Severus didn't know why the boy had agreed to do it. Was it a way to gain power, to get the chance to lord it over him? First save him, no matter how it might go against the grain, so that later he could taunt him with the knowledge that now he was only another student with no way to fight back. So that he could hold Severus in the hollow of his hand, knowing that he could hold the threat of Azkaban over his head. Surely it was just a new method of torture, more ingenious than any his father had ever devised?

At first Severus had really believed that, had waited for the first blow to fall. But it hadn't come. It never did, and now Potter had not only not taken advantage of weakness but had scared away the wolves. It made no sense. James would never—

Severus stared into those lazy, amused, dangerous eyes. This was not James. It never had been.

"Why did you – help me?" Not just now, he meant, but then too.

Potter gave him a long look. "You looked like you could use a friend."

"I don't— That's not enough!"

"Why did you save my life over and over?"

Severus was silent.

"Exactly." He shoved himself off from the wall and turned away.

Severus took an abortive step after him. "Potter—" But the words stuck in his throat and he couldn't say them.

Potter turned and tilted his head, studying him. "It's okay, Snape." He shrugged. "You don't have to like me." He smiled wistfully and slouched off, his hands in his pockets.

Severus stood there and watched him go.