It was late, almost curfew.

Severus Snape walked briskly to his classroom. He had left Potter scrubbing the room from floor to ceiling while he went to take care of a few pressing matters. Ordinarily, he didn't leave students unsupervised in his classroom during detentions, particularly Gryffindors, but Potter was a diligent worker and (loathe though he was to admit it) didn't exhibit the tendency towards pulling pranks which had characterized his father. Oh, the boy got into plenty of trouble, but it was seldom entirely his fault.

Not that Snape would ever admit that aloud.

The fact of the matter was that the Potions Master had needed to complete a few tasks before curfew so that he could leave as soon as he sent Potter back to Gryffindor tower. That night would be his last opportunity to collect a rare moonflower for his stores and he wanted to be able to get as many as he could.

The man allowed his gaze to sweep across the Potions classroom as he entered, noting that all visible surfaces were impeccably clean. Probably the cleanest this room has been in months, Snape thought ironically. He also didn't fail to notice that Potter was nowhere to be seen, having no doubt excused himself the moment he thought he was finished.

Deciding that another detention would be in order for the delinquent Gryffindor, Snape waved his wand towards the open door to the cleaning closet, closing and locking it with a single motion. Quickly crossing the room, he entered his office to make sure everything there was in its proper place before setting off.

Harry stretched upward, trying to return the mop bucket to its designated hook. Somehow, it had been easier getting it down. Granted, he hadn't been stiff from scrubbing for nearly three hours when he'd retrieved it from the cramped supply closet. He had nearly succeeded in replacing it when the door shut with a click of finality, leaving him standing on his tiptoes in pitch blackness.

Oh, no, oh, no, oh, no... Heart lodging itself in his throat, the boy slowly lowered himself back down so he was standing flatfooted in the cramped space, bucket still in hand. Turning, he took the half-step to the door and tried the handle.

It was locked. He was locked in with the cleaning supplies. His breathing started to become a little shaky. There had just been some sort of mistake. A draft, perhaps, had blown the door shut. Professor Snape would come back to check on his progress and find him. The man always checked his work – the man usually had something to criticize. Of course, he would be back to check his work. Any moment, his teacher would come back and find him and let him out...

He wasn't in a cupboard! This was bigger than his cupboard. No. No, it wasn't bigger than his cupboard. The ceiling was a lot higher, but the space wasn't any bigger, at all. In fact, it might even be smaller...

He was in his cupboard. He'd been locked in. Again. Why, of why, did he have to open his mouth? That was usually what did it – his cheek. Uncle Vernon hated it when he got mouthy. Aunt Petunia didn't put up with any of his sass, either. That had to be why he'd been locked in again... why they had taken his light bulb. He'd finished his chores – he knew he had finished his chores!

Dropping the bucket, the clatter echoing deafeningly in the small space, Harry grabbed for the knob and began desperately twisting at it, even as he began to pound against the door with his other hand. He didn't care if he was hit for making such a racket – he didn't want to be shut in that cramped little room in the dark.

Severus' head snapped up as a sudden racket came from his classroom. Closing and warding the drawer he kept his grading in, the Potions Master cautiously approached the door leading from his office, peering into the seemingly lifeless chamber beyond. The rattling of a locked doorknob being repetitively and ineffectually twisted, accompanied by a steady banging, came from the cleaning closet.

Suddenly, the handle grew silent. A few more thumps were issued before the banging also ceased.

Warily, Snape approached the narrow door. He paused to listen, baffled by the ragged breathing coming from its other side. What in Merlin's name..? Murmuring an unlocking spell, he cautiously turned the knob, nearly finding himself with arms full of second-year Gryffindor as the door swung open.

“Potter -” he began, but before he could continue, he was interrupted by what he abruptly realized was a very distraught twelve-year-old.

“I'm sorry, sir!” Harry exclaimed tearfully. “I'm sorry! I didn't mean t-to be cheeky – honest. Please, sir, I'll be good. I promise. Please... I'll be good!”

“Potter, what -”

“Please, uncle, I'm sorry. Can't I at least have my l-light?” the boy implored.

Snape took the boy by the shoulders, his own stomach churning at the violent flinch which coursed through the thin frame. “Potter,” he said firmly, “look at me.”

Fearful green eyes snapped up to meet his gaze, though, he suspected the teen wasn't really seeing much of what was around him.

“Who am I?”

Potter stared at him, some of the clarity seeming to return to his eyes. Snape watched as the boy's lips silently moved around what appeared to be the word 'uncle' before he blinked, confusion overtaking his features. “P-professor?”

“Do you remember where you are?” Snape asked.

Another pause before answering, as the boy's gaze flitted about the room. “Hogwarts,” he murmured quietly.

“Potter,” the man wanted to know, “what were you doing in the cupboard?”

“You locked me in!” Harry exclaimed in sudden realization. Snape wondered if the boy knew how hurt he sounded. The boy shrugged to dislodge the hands still holding his shoulders and the man obligingly released him. Pushing past the older wizard, Harry quickly put distance between himself and his recent prison.

“I did not know you were still here,” Snape told him. “I thought you had already left.”

“You hadn't excused me, yet,” the boy returned accusingly. “I was trying to put the bucket back!” He gestured to said bucket, which still lay on the floor of the closet.

“I admit... that I hadn't thought to look there.”

“Well, you should have! Sir!” Harry quickly diverted his gaze, frantically picking at his fingers, though the action was unconscious. Clearly, he had still not recovered from his little... episode.

Snape stared at the boy's bowed head for a moment. “I wish to speak about your reaction.”

Potter tensed, his hands' movements halting, but he made no move to answer.

“It seems apparent that you were suffering some sort of flashback,” the man continued. “Potter, does your uncle – or aunt – lock you in a cupboard at home?”

The boy shook his head sharply, clearly more in refusal than actual response.

“Potter...”

“Sir, it's past curfew,” Harry blurted, still refusing to look back at him.

Snape suppressed a sigh. “Quite right,” he conceded. “You're dismissed, Mr. Potter.”

“Thank you, sir,” the faint whisper was strained and carefully controlled. Spinning about, Harry quickly made his escape.

The Potions Master frowned. The trembling bundle of nerves and trepidation that had just departed his classroom was nothing like the boy he had known or imagined. Finding himself deeply unsettled by this new Potter, he strode straight for the floo in his office. He would be speaking to the headmaster.

Immediately.