The descent into the Slytherin dungeons was a plunge into another world. The air grew sharply colder with every step, carrying the damp, mineral scent of the Black Lake. Inside the common room, the ambient light was a murky, underwater green, cast by silver lamps and the roaring fire in a grand, carved fireplace. Older students occupied the dark leather sofas, their conversations dropping to hushed murmurs as they watched the new arrivals with calculating eyes.
Harry shivered slightly, pulling his black robes tighter. He was used to small, dark spaces, but the cupboard under the stairs had never felt this vast or ancient.
"Keep your chin up, Potter," Draco murmured, stepping smoothly to his side. The blond boy looked entirely in his element, his aristocratic posture perfectly suited to the gothic surroundings. "They're just sizing us up. It's how things work down here."
Draco led the way to the first-year boys' dormitory, a circular room with five four-poster beds hung with deep emerald velvet curtains. Silver lanterns cast a cool glow over the rough-hewn stone walls.
"First rule of Slytherin," Draco announced, dropping his trunk at the foot of a bed near the center. He gestured for Harry to take the one beside it. "We present a united front to the rest of the school. No fighting in the corridors, no losing points where the Gryffindors can see. We settle our differences down here."
Harry sat on the edge of his mattress, testing the springs. "And inside the common room?"
"Inside, it's about who you know and who you can trust," Draco said, a smug but helpful smile playing on his lips. "You handled Farley well at the feast. She's a fifth-year prefect—tough, but she respects a spine. Just remember to address the prefects respectfully. They control the common room hierarchy."
Harry nodded, absorbing the information. He glanced around the room. Vincent Crabbe and Gregory Goyle were already unpacking, moving with heavy, unhurried steps. They took the beds nearest the door, acting as a natural buffer, already falling into the roles of Draco's bodyguards.
It was the fifth boy who caught Harry's attention. Theodore Nott was quietly organizing his books, his movements precise. He was a stringy boy with shadows under his eyes. When Draco loudly claimed the best bed, Nott merely watched, his silence heavy and suspicious. He didn't offer his hand, and Harry didn't push for it. The lines were already being drawn.
Back in the common room earlier, Harry had noticed Pansy Parkinson holding court among the first-year girls near the fire. She had a sharp, assessing gaze, and as Harry passed, she had offered a small, calculated smile. It wasn't a welcoming smile; it was an acknowledgment of his status. Harry realized quickly that his presence here was an anomaly. The Boy Who Lived, sitting in the heart of Slytherin. He could hear the faint murmurs of the older students echoing off the stone walls—debating his worth, his power, and what his alliance with the Malfoy heir meant for the house's political future.
"They're waiting for me to mess up," Harry said quietly.
"Let them wait," Draco replied, tossing a silver-backed hairbrush onto his nightstand. "You're with me. As long as you don't start acting like a Hufflepuff, we'll run this year."
The next morning, the subterranean chill made getting out of bed a reluctant chore. The green-tinted light filtering through the high dungeon windows made everyone look slightly ill. Harry dressed in his new uniform, the green and silver tie feeling like a heavy badge of his new reality.
At breakfast in the Great Hall, the enchanted ceiling mirrored a crisp, clear sky, a stark contrast to the gloom below. Harry ate his porridge quietly, acutely aware of the stares. From the Gryffindor table, a red-haired boy—Ron Weasley, who had refused to sit near him on the train after Draco arrived—shot him a look of pure, betrayed resentment. Harry ignored it, focusing on Draco's running commentary about the faculty.
Their first class was Potions, held in a dungeon classroom that was even colder than the common room. The air was thick with the acrid scent of preserved specimens and ancient damp. Pickled animals floated in murky glass jars lining the walls, casting eerie, distorted shadows in the dim candlelight. Water dripped somewhere in the distance, a hollow, rhythmic sound that only heightened the room's oppressive tension. Harry took a seat at a heavy wooden workbench beside Draco, resting his hands on the scarred, stained surface.
The heavy wooden door slammed shut with a resounding echo. Professor Snape swept into the room, his black robes snapping behind him like a giant bat's wings. The chatter died instantly.
Snape reached the front of the class and turned, his dark eyes sweeping over the students before locking onto Harry. A sudden, sharp prickle of heat flared behind the lightning-bolt scar on Harry's forehead. He forced himself to keep his face blank, gripping the edge of his stool. The pain wasn't as blinding as it had been at the feast, but it was a distinct, warning throb.
"You are here to learn the subtle science and exact art of potion-making," Snape began, his voice barely above a whisper, yet it carried to every corner of the silent room. "As there is little foolish wand-waving here, many of you will hardly believe this is magic."
Snape's speech was mesmerizing, cold and precise. He spoke of bottling fame, brewing glory, and even putting a stopper in death. The words hung in the freezing air, demanding absolute attention. When he finished, he picked up the roll call. He paused at Harry's name.
"Ah, yes," Snape said softly. "Harry Potter. Our new... celebrity."
Draco shifted slightly beside him, a subtle show of solidarity. Harry kept his eyes locked on Snape, fighting the urge to rub his forehead.
"Tell me, Potter," Snape said, stepping down from his podium and gliding closer. "What would I get if I added powdered root of asphodel to an infusion of wormwood?"
Harry's mind raced. He had read his textbook, *Magical Drafts and Potions*, but he didn't have a photographic memory. He remembered the names, though. "A sleeping potion, sir?" he ventured, his voice steady despite the nervous flutter in his chest. "A very strong one."
Snape's eyes narrowed infinitesimally. The scar twinged again. "Acceptable. It is known as the Draught of Living Death. Let us try another. Where would you look if I told you to find me a bezoar?"
"In the stomach of a goat, sir," Harry replied, recalling the strange fact that had stuck out to him during his reading. "It saves you from most poisons."
Silence stretched in the damp air. Snape's gaze was heavy, scrutinizing every inch of Harry's face, searching for something—arrogance, perhaps, or weakness. Harry offered neither. He just sat there, a cautious eleven-year-old trying to survive his first day.
"And what is the difference, Potter, between monkshood and wolfsbane?"
Harry hesitated. He didn't know this one. He could feel the eyes of the Gryffindors on the other side of the room, and the quiet, assessing stares of his fellow Slytherins. "I don't know, sir," he said evenly.
Snape stared at him for a long moment. The hostility Harry had expected didn't come. Instead, there was a guarded, complex calculation in the Potions Master's eyes.
"They are the same plant, which also goes by the name of aconite," Snape said, his tone perfectly neutral. "Well? Why aren't you all copying this down?"
There was a sudden scramble for quills and parchment. Harry exhaled a slow, quiet breath. He had survived the interrogation.
The rest of the lesson was spent brewing a simple potion to cure boils. Harry focused on the instructions written on the blackboard. The recipe required precision. He carefully weighed out his dried nettles, his hands steady despite the lingering tension in the room. Beside him, Draco was crushing snake fangs with a brass pestle. The blond boy's movements were practiced and confident, a clear sign that he had been tutored in the basics before ever setting foot in Hogwarts.
Harry didn't have that advantage, but he was used to cooking under Aunt Petunia's harsh scrutiny. He knew how to follow a recipe, how to watch the heat, and how to learn by observing others. He watched Draco's precise angles and timing, then mimicked them, crushing his own fangs into a fine powder.
Snape prowled the aisles, his black cloak brushing the stone floor without a sound. He criticized almost everyone, his sharp remarks leaving a trail of nervous mistakes in his wake. He lingered near Harry and Draco's workbench.
Harry felt the drop in temperature before he heard the voice.
"The horned slugs must be stewed, Potter, not boiled," Snape's cold voice murmured right behind Harry's ear.
Harry froze. The proximity made his scar give a faint, uneasy pulse, a dull echo of the sharp pain from the feast. He didn't turn around.
"Yes, sir," Harry said evenly. He reached out and carefully adjusted the brass dial on his burner, lowering the flame until the bubbling liquid settled into a gentle simmer.
Snape watched the cauldron for a second longer. Harry could feel the Potions Master's gaze boring into the side of his head. Then, with a soft rustle of fabric, Snape moved on to sneer at a Gryffindor boy whose cauldron was emitting thick, acidic green smoke.
When the bell finally rang, Harry bottled his potion—a passable, if slightly lumpy, blue liquid. Snape accepted the vial without a word, his face a mask of indifference.
As they walked out into the damp corridor, Draco nudged Harry's shoulder. "Not bad, Potter. I thought he was going to skin you alive for a moment there, but you held your nerve. Most people would have crumbled."
"He was just testing me," Harry said, rubbing his forehead discreetly. The dull ache was fading, but the mystery of it remained. Why did Snape's presence make his scar hurt? Was it a warning? A side effect of whatever magic had left the mark in the first place?
"Everyone's testing you," Draco corrected, a smirk playing on his pale face. "But you're doing fine. Come on, let's get to Transfiguration before Nott takes the best seats."
Harry walked beside his new friend, feeling the weight of the silver and green tie. He was in Slytherin. He was surrounded by people who would use him if they could, and a Head of House who watched him like a puzzle waiting to be solved. But as he matched Draco's confident stride, Harry felt a cautious sense of belonging. He would learn the rules, he would watch his back, and he would figure out the secrets this castle was hiding.