Snape's sudden choice to cover the final chapter on werewolves stirred an immediate murmur among the students. But after watching Snape dock points from both Harry and Hermione, no one dared speak up again.
By the end of the lesson, everyone had at least a basic grasp of werewolves — though Snape had gone out of his way to hammer home the signs and clues for spotting one. Most of the class sat through it in bored silence, but Sean noticed that Hermione, quick as ever, had turned pale halfway through. It was obvious she'd caught what Snape was hinting at.
When the bell rang, Hermione didn't even wait for Harry and Ron. She shot out of her seat and headed straight for the library — clearly planning to check every book she could find about werewolves.
Sean and Blaise left the Defense Against the Dark Arts classroom together but parted ways near the first-floor staircase. Blaise was off to meet Andy to watch the Quidditch team's training, while Sean followed Snape down the corridor to his office.
Once inside, Sean shut the door behind him."Professor, about the third substitute ingredient — does it work?"
Snape turned, his face as unreadable as ever."I tested it before class. There's a problem."
Sean frowned. By his calculations, there shouldn't have been any issue — but theory and practice were two different things. Calculations couldn't always predict every reaction once the cauldron was bubbling."What's wrong with it?" he asked.
Snape gave him a flat look."The effect is nearly identical to the original material — the difference is so slight it's negligible. But there's a conflict. One component in your new substitute reacts badly with an ingredient in the first substitute you chose. When they're brewed together, they repel each other and destabilize the potion. The result is an explosion and a ruined batch. It's an inherent conflict — it can't be resolved by brewing technique alone.
Snape folded his arms."You'll have to pick which to replace — the first substitute or the third. One of them must go."
When Sean first started researching substitute ingredients, he'd known sooner or later he'd run into conflicts between them — but he hadn't expected to hit that wall so soon, and he was still only in the first stage of his work.
"I'll go back and rethink it," Sean said. "I'll try to find milder ingredients that won't clash — maybe that'll cut down on conflicts later."
Snape gave him a curt nod."I'll keep testing things on my end, too. Get on with it."
Sean gathered up Snape's test samples and went straight back to his dorm, then headed for the library with all the notes he'd collected so far.
This time he didn't bother with a quill — instead, he pulled out the pencils he'd brought with him at the start of term. To keep his calculations clear and quick, he'd stocked up on pencils and stacks of scrap paper. If only Hogwarts allowed Muggle electronics — a calculator or a laptop would have made all this so much faster.
He lost track of time. It wasn't until Madam Pince appeared at his table that he even looked up. She glanced at the stacks of notes and scribbled pages, then at the five or six empty bottles of spirit-recovery potion beside him. Though she usually kept a stiff distance from students, her tone softened a little.
"Time's up — the library's closing."
Sean blinked, dazed, and turned to look at the dark windows."It's dark already? That was quick…"
Madam Pince sniffed."If you go now, there's still time to find a house-elf to bring you something to eat. You've not eaten, have you?"
Sean rubbed his eyes and started gathering his papers."You're right — I haven't. Thank you, Madam Pince. I'll remember next time."
She gave him a sharp nod."Good. And don't forget your rubbish — take every scrap with you."
"Yes, Madam Pince."
He packed up fast, but instead of heading back to the Slytherin common room, he made straight for the kitchens to ask the house-elves for something warm to eat. Once he had food and drink in hand, he turned and went straight to the Room of Requirement — ready to keep working.
Sitting comfortably in the Room of Requirement, Sean ate and drank just enough to steady himself, then downed two potions — one to ease the exhaustion in his body, the other to clear his mind.
After a brief rest, once the potions took effect, he picked up his pencil again and threw himself back into the unfinished calculations.
By the next morning, Sean stood at the main doors of Hogwarts, staring out at the steady drizzle. With a resigned sigh, he drew his wand, cast a quick waterproofing charm over himself, then flicked his wand tip to conjure an umbrella before stepping out toward the Quidditch pitch.
By the time he arrived, the match was already in full swing. Gryffindor and Hufflepuff were facing off in the air — but compared to a match against Slytherin, both teams were far more civil. None of the usual borderline fouls and dirty tricks were happening here.
Sean headed for the Slytherin stands. Since neither team playing was Slytherin, most of his housemates hadn't bothered to come out in the rain. Still, to his mild surprise, he spotted Malfoy and his gang loitering there — whether to watch Harry or just to gossip, who could say.
Spotting Blaise, Andy, and Jason, Sean trudged over, yawning. Andy had already dried off a seat with a spell, so Sean folded up his umbrella and sat down under the stand's canopy.
Blaise turned, ready to greet him — but when he got a good look at Sean, he froze."Sean… what did you do last night? Your dark circles are terrifying!"
Andy leaned forward too, eyes widening."You didn't sleep at all, did you? We looked for you this morning — your bed was empty. You stayed up all night?"
Sean rubbed his temple, then shrugged."Yeah. I found a quiet spot and finished my calculations and draft. I just turned the paper in to the professor before I came here. This stage is done — now I need real rest, because the next stage is going to be even tougher."
He'd barely finished speaking when a sudden roar of alarm rose from the stands. Sean's head snapped up — in the sky, Harry had just dived after the Golden Snitch but was now plummeting from his broom, limp.
At the same time, a swarm of Dementors spilled from the low, dark clouds overhead — sweeping straight toward the stands, drawn to the students like moths to flame.