Snape continued to watch the boy, and Potter continued to do… nothing much. At mealtimes, he sat alone or with Draco; once or twice Snape spotted him at the Ravenclaw table with Hermione Granger. He sat on his own in the common room, curled up in an armchair in front of the fire; not reading, not doing anything but watching the flames. Once, Snape went by the Quidditch pitch when the first-years had their flying lessons. Potter was zooming around the pitch closely behind Draco, and there was an expression on his face… not joy exactly, but something very close to it. Snape noticed that the boy was a gifted flier.

Not so much a gifted potions brewer. Average at best, but then they all were, with the possible exception of Hermione Granger. At least none of his Slytherins had managed to melt three cauldrons and vanish a fourth, as Longbottom of Gryffindor had done. Snape was so busy keeping an eye on the clumsy dunderhead that his attention to the rest of the class suffered. As usual, Potter blended into the blackground, and Snape never spared his work more than a passing glance.

Then came the day they brewed the Forgetfulness Potion. In retrospect, Snape had to admit that the incident had taken him completely by surprise, as if he had never noticed anything… odd about Potter before. It shouldn’t have; he knew that. He should have been prepared.

The Forgetfulness Potion was one of the most difficult draughts taught in first year, not least because it involved essence of the Snargaluff Pod, an acid-like substance that had to be handled with extreme care. Snape began the lesson by demonstrating its effects on a piece of parchment – a very satisfying moment when twenty-four pairs of eyes widened at the parchment’s instant incineration – and showed them a graphic picture of a wizard who’d dripped Snargaluff Succus on his foot.

“And… and it can’t eat its way through the glass?” Pansy Parkinson asked, with an anxious glance at the innocuous green bottle in front of her.

Had it been one of the lions asking this, they would have been pelted with biting sarcasm; as it was, Snape only narrowed his eyes at the girl.

“Be assured, Miss Parkinson, that my potions equipment is perfectly safe.”

He wrote the instructions for the potion on the blackboard, and had Goyle read them out loud to the class (not least because he wanted to make sure the boy did read them). As the students lit their fires and adjusted their scales, he swept up and down the room, watching their progress and snatching Longbottom’s bottle of Snargaluff Succus from his desk a second before the boy knocked it over with his elbow.

“Do you wish to examine the bone structure of your foot in vivo, Mr. Longbottom, or are you simply one of the clumsiest students ever to set foot across this threshold?”

The boy trembled, looking about to cry. Snape sighed and set the bottle down again, safely out of Longbottom’s reach. One of these days, the little idiot would exterminate the entire Potions class, and then Albus would be in a pickle trying to find a new Boy-Who-Lived… never mind another double agent to spy on the Death Eaters.

The class began brewing, and Snape lingered near Longbottom’s desk to prevent any major catastrophes. The boy’s hands shook, and he crushed most of the lacewing flies he was supposed to cut into fine pieces. Snape bit his tongue to keep himself from remarking upon it. Minerva had asked him to be more “lenient” towards the boy – as if it were his fault that Longbottom could no more brew a potion than Filch could dance the Dying Swan.

Half-way into the lesson, not a single potion showed the translucent shimmer that was the desired intermediate result. Snape was not surprised. It was a difficult draught to brew, and he’d only set this task so early in the year because he intended to have a repeat lesson later on. Draco had done well at first, before he forgot to add the second ounce of Screechsap. Now he was stirring dejectedly what looked like pea soup.

Snape was leaning over Longbottom’s shoulder, advising him how to stew his tubeworms – “do not turn them around before they are done, stupid boy” – when a loud gasp behind him made him jump. Gasps of any kind never boded well in Potions class. Turning around, he saw Vincent Crabbe standing over his cauldron with an empty flower pot in hand and a horror-struck expression on his face. The boy had managed to tip his entire lovage plant - roots, earth and everything - into his cauldron.

The ruined potion was hissing and emitting copious amounts of steam, filling the air with strong-smelling fumes. The students around Crabbe began to cough and wave their hands in front of their faces, rushing from their work stations and knocking over ingredients in the process. Snape prayed that none of them would accidentally spill Snargaluff Succus over themselves.

“Stay calm!” he bellowed. “The fumes aren’t dangerous, they’re merely-“

“Pro – Professor!”

Snape turned around, and saw Longbottom backing away from his cauldron. The potion inside was bubbling like a live thing, dangerously close to boiling over. Its greenish hue told Snape that Longbottom had already added the Snargaluff Succus.

“Turn down the heat, boy!”

Longbottom was clearly panicking between the white fumes billowing around him and his irate professor.

“I – I – “

The first bubble splashed over the rim of the cauldron and onto the floor, eating a hole into Longbottom’s schoolbag.

“Aguamenti!” A well-aimed jet of water from Snape’s wand hit the fire under Longbottom’s cauldron, extinguishing the flames at once. Not that it did much to diminish the pandemonium that had broken out.

Longbottom was sobbing hysterically, clutching his damaged bag, while the rest of the class knocked over scales and chairs trying to get away from Crabbe’s fuming concoction.

“Out!” roared Snape. “Everybody out!”

Despite the fumes, the students seemed to find their way to the door very quickly, gathering up their things as they ran. Barely restraining himself from throwing Longbottom bodily out of the room, Snape snarled at them to get moving and slammed the door shut behind them. Merlin, but he hated this job.

The classroom was a mess. Broken bottles on the floor, ingredients strewn across the tables. Longbottom’s potion had coalesced into a stinking mass. And still, Crabbe’s cauldron was emitting fumes that drifted through the room like mist across the Dark Lake.

Snape grabbed a piece of cloth, held it in front of his mouth and strode through the fumes towards Crabbe’s work station. No doubt the smell of lovage would linger for weeks to come. Bloody little incompetents, why couldn’t they simply follow the instructions?

He vanished Crabbe’s potion with a flick of his wrist, and was pointing his wand at Longbottom’s cauldron when a sound behind him made him stop in his tracks.

Someone was… keening. Keening like an injured dog.

He whipped around. “Who’s there?”

Damn fumes, he couldn’t see a thing. Batting angrily at the air, Snape took a step towards the sound. It seemed to be coming from a corner of the room.

“Who is there? Show yourself!”

The keening grew louder, now sounding of all things as if someone were laughing… a high-pitched, grating laughter.

Severus.

Snape stood frozen. That voice had not just hissed in his ear, spoken to him from the realm of shadows. It could not be.

Gripping his wand more tightly, he stepped towards the keening sound, and his hand shook only the slightest bit as he raised it to blast the fumes aside.

Potter stood with his back to him, his cauldron between them. The boy’s shoulders were hunched, as if he were in pain. The keening was coming from him, and at the same time it seemed to be coming from everywhere, from every corner of the room and from within Snape’s own mind.

“Potter? What is the meaning of this?”

Severus.

No, it could not be.

“Potter!” Snape yelled. “Turn around and look at me!”

He had not expected the boy to obey, but Potter did, turning slowly on the spot. It was all Snape could do not to take a step back.

The boy’s eyes were white, soulless under the glaring red scar, his face contorted in pain and insane ecstasy alike.

“Potter?”

One hand came up, a spidery claw that was nothing like a child’s hand. Potter stretched it out towards him in a gesture both defensive and strangely beseeching. Spit trickled down his chin from his open mouth. As Snape watched, the boy’s teeth clamped and bit down on his tongue.

“No!” Snape took an involuntary step forwards.

Potter screamed. For a second, his eyes returned to their normal bright green and Snape saw insane fear in the boy’s face. Then the milky white was back, and keening laughter resounded in the room.

Severus… listen to me.

“No!” Snape shouted, raising his wand. Potter had spoken and yet he had not; the high, grating voice seemed to come from deep within the child.

“Stupefy!” Snape yelled, more out of instinct than anything else. Potter did not duck away from the red beam of light; he batted it aside like a mosquito and laughed.

Severus, you fool.

Slowly, very slowly, the boy reached into the cauldron in front of him. Snape watched, horrified, as his hand touched the acid substance within and immersed itself, deeper and deeper.

“No…”

Cold, high laughter filled the room as Potter pulled his hand out again; his whole, undamaged hand, in which he held a viscous blob of liquid.

“Potter…”

The liquid was hurled towards him, and only his well-honed reflexes saved him from catching a face-full of acid. A few drops of it landed on his robes, burning holes in the thick fabric and leaving searing pain behind.

Fuck you, Severus! the boy screeched, this time plunging both arms into the potion.

“Impedimenta!” Snape yelled, blocking the new handfuls of acid that were flung his way. “Potter, can you hear me?”

Fuck you fuck you fuck… you…

Potter dropped to his knees, his head thrown back. Blood was dripping from his open mouth, and he drew his ragged fingernails across his cheeks, leaving long, red scratches behind. Snape saw the white eyes close, and acted without a moment’s thought.

“Stupefy!”

This time, the spell hit home. Potter slumped to the floor, his glasses askew, eyes staring blankly. Green eyes, slightly bloodshot. The white sheen had disappeared. Whatever had been looking at Severus through Harry Potter’s eyes seemed to be gone.

Snape knew better than to approach the boy immediately. The… thing inside him might be hiding, trying to trick him.

“Scourgify,” he said softly, cleaning the potion off Potter’s limp hands. The acid had not left a single trace on the boy’s skin.

Potter moaned, stirring feebly. Snape took a careful step forward. “Potter?”

Another moan, one that sounded very much like a little boy in pain.

“Harry?”

No, there was no trace of that high voice, or the entity that had stared at him with those white eyes.

“Finite incantatem,” Snape said, lifting the stunning spell. The boy coughed, brought a hand up to straighten his glasses, and began to sit up.

“Pro… Professor Snape?”

“Yes,” Snape replied. “Do you remember what happened?”

Harry stared at him. Slowly, he brought shaking fingers to his chin, touching the blood and looking down at his red fingertips. He raised his head and took in the mess around them, the knocked over chairs and scattered ingredients.

“I…” His voice was a whisper, so soft that Snape hardly caught the words. “It… it was him, wasn’t it?”

“Him?” Snape repeated slowly. “Who are you talking about?”

“Him,” Harry whispered, drawing his knees to his chest. Tears were running down his face, but he didn’t seem to notice them. “Him… I’m sorry…”

Snape looked at the boy and was once again struck by how small he was. Small and frightened, and far too young to be a part of this. Any of this.

“No apologies are required,” he said, slightly awkwardly. “Your classmates are mostly responsible for the classroom’s current state of disarray.”

“I can’t stop him,” Harry whispered. “He… he’s… stronger…”

“I know he is, child.” Snape said it quietly, not even sure if Potter had heard him. “You’re bleeding. Let’s get you to the infirmary.”

Potter nodded and wiped at his cheeks in a very childlike gesture. He began to get up, and had almost managed to stand when his knees buckled under him, sending him back to the floor.

“S-sorry, Professor…”

The boy was white as a sheet and swaying on the spot. No way he could climb several sets of stairs in his condition.

“Come on then, Potter.” Snape kept his voice gruff to lessen the embarrassment for both of them.

The boy allowed himself to be picked up and immediately leaned his face against Snape’s chest. Snape took the uncharacteristic gesture as a sign that the boy was still teetering on the edge of a breakdown, seeking comfort wherever he could get it.

Potter was very light in his arms, as if he were carrying a bundle of rags. Snape glanced at his face, and saw a single drop of blood trickle down slowly from the scar. The boy’s eyes were closed, his breathing shallow. Snape could feel him shiver as if he had a fever.

“You’ll be feeling better soon,” he said, wondering what prompted him to offer comfort to this child.

Harry gave no reply. He never opened his eyes, one of his hands seeking the front of Snape’s robes and closing around the fabric. It was the gesture of a much younger child; a very primal plea for protection.

“Soon,” Snape repeated, because he could think of nothing else to say. “I promise.”