"The troll's been killed!"

That night, the news exploded through Hogwarts like wildfire.

By morning, even the most dedicated late sleepers were out of bed with pillow lines still on their cheeks. They hadn't even washed their faces properly, just rubbed their eyes, yawned their way into their robes, and ran outside in the cold.

Hogwarts had slipped fully into November. Frost blanketed the ground in silver-white sheets, crunching under every hurried step. The wind cut straight through cloaks and robes, sneaking into bones like it had a personal grudge against warmth.

But none of that could stop the excitement.

There it lay in the courtyard, an enormous troll corpse, headless and frozen, sprawled across the stone like a fallen mountain. Students gathered in a tight ring around it, eyes wide, voices buzzing. Filch had hammered a sign into the ground in front of it, which read:

"Mr. Vaughn Weasley and Mr. Ron Weasley each lost 10 house points for leaving the Halloween feast without permission. However, after encountering a mountain troll, the two acted with courage and resourcefulness. Mr. Vaughn Weasley dispatched the troll with advanced spellwork, aided by Mr. Ron Weasley. Therefore, Slytherin is awarded 30 points, and Gryffindor 20."

Short, formal, and utterly unsatisfying to the dozens of students practically vibrating with curiosity.

Fortunately, today was Halloween. No classes. All the time in the world to gossip.

Gryffindor had already started the celebrations the night before. They were now hosting a full-blown "victory breakfast" in their tower. The Weasley twins had gone on a wild invitation spree, handing out party slips to every house like it was Christmas.

Everywhere they went, they cheered:

"Our little brother killed the troll!"

By the time the other houses arrived, Percy Weasley was already standing at the entrance, badge polished to a mirror shine, wearing the proudest expression known to wizardkind.

"Welcome to the celebration of my brothers' victory," he announced with the air of someone who had also personally slain a monster. "Yes, yes, both Vaughn and Ron are fine examples of Weasley bravery. Takes after the family, really."

The Gryffindor common room had been efficiently cleared and transformed. Long tables were lined end-to-end, heaped with food from the castle kitchens, thanks to the ever-industrious house-elves.

One table was surrounded on all sides, packed with students eagerly listening as Ron Weasley, cheeks pink with excitement, launched into his retelling of the night's events.

"…It was at least twenty feet tall... don't interrupt me! Yes, I know trolls are only twelve feet tall, I'm just saying that's what it looked like. I mean, you try looking at that thing charging you and not overestimating."

His eyes practically sparkled as he waved a half-eaten pie for emphasis.

"Then Vaughn shouted 'Confringo Maxima!' and BOOM! The troll's club shattered like a twig, pieces flying everywhere! Dust, smoke, skin, troll flesh flying through the air! The whole place was shaking, and the troll screamed like - AAARGH!"

Half the crowd jumped. The other half grinned and leaned in closer.

Even some older students had gathered around, enthralled. They recognized most of the spells Ron mentioned, though his description of the effects was, to put it mildly, imaginative.

One wide-eyed first-year asked in a reverent whisper, "Ron, what spell did you use?"

Ron puffed up instantly. "A very powerful one," he said confidently. "Blinded the troll right in the eyes! That gave Vaughn the opening."

Then he dove back into his dramatic retelling. In his version, the battle had been a thunderous back-and-forth between beast and boy. The troll had been terrifying, the victory hard-earned, and Vaughn's final spell had blasted it into chunks too messy to be reassembled.

Why did the troll's body still look mostly intact in the courtyard?

Obviously, Ron explained, the professors had magicked it back together for display. Except for the head, of course.

"Vaughn blew that clean off. Bits of brain everywhere. No way to reattach it," Ron added gravely.

In the corner of the room, Harry and Hermione were sitting on a cushioned bench, keeping a low profile. They had only just returned from the hospital wing, where Madam Pomfrey had forced a large calming draught down Harry's throat, worried about the splitting headache he'd suffered the night before.

Harry had been listening intently until Hermione leaned over and muttered, "Ron's making half of that up."

"I don't know," Harry whispered back. "You saw what Vaughn did. And that dark wizard too. Those spells…"

"I'm not saying Vaughn isn't powerful," Hermione said. "But Ron's acting like he was dueling the troll alongside him for an hour. It couldn't have been that close. Vaughn handled it too quickly."

Harry paused, then frowned and looked down at his bread roll. He rubbed his forehead absentmindedly. After a while, he said quietly, "Hermione, do you think… do you think Dumbledore asked us to keep quiet about the fourth floor because of something serious?"

The question had been burning in his mind since last night.

He had too many unanswered questions.

Who was that dark-robed man? Why had Harry's scar exploded in pain the moment he saw his back?

When Vaughn had overpowered him, the man had cried out for his "master." Who was that?

And how had Harry been able to feel the man's thoughts?

He had wondered if he'd been cursed. But Madam Pomfrey had examined every inch of him with every diagnostic charm she knew. No traces of dark magic. Nothing at all.

She'd said it was fear-induced hallucinations.

Harry wasn't so sure.

Hermione, after a moment of thought, set down her book and said, "I think Dumbledore suspects something. If he thought it was just some random intruder, he'd have the entire castle on lockdown."

"Then why keep it quiet?"

"Because he thinks the dark wizard is someone inside the castle. A professor."

Harry stared at her, stunned.

A professor? That couldn't be.

But the more he thought about it, the more it made sense. It was the only explanation that fit.

Then came the real question.

Which professor?

Names started flying through his mind until one rose to the surface almost naturally.

"Snape," Harry muttered.

Hermione shook her head immediately. "No."

"You always defend the teachers like they're saints," Harry argued. "Snape's awful to you."

"Maybe. But last night, he went to the dungeons with Dumbledore. He couldn't have been on the fourth floor."

"Professor McGonagall told us the dungeons are huge. What if they split up? Snape was the last to show up at the headmaster's office."

"It still doesn't make sense!"

Hermione crossed her arms and hesitated, then said reluctantly, "Do you remember the spell Vaughn used last night? Sectumsempra."

Harry nodded. Vaughn had used it to slice right through the dark wizard's shielding spell. It had been ridiculously cool.

Hermione said quietly, "Vaughn told me Snape taught him that spell."

Then she snapped her book shut, gathered her things, and stood up.

"Where are you going?" Harry asked.

"To check on Vaughn," Hermione said briskly. "You're sitting here listening to Ron brag and accusing professors. Neither of you even thought to see how Vaughn is doing!"

Flushed with guilt, Harry snatched up a piece of toast and rushed after her.