The days at Hogwarts settled into a routine, but an undercurrent of unease lingered beneath the surface. Harry couldn't quite place it, but something felt off.
It started with little things, whispers among the professors hurried conversations cut short when students passed by, and the occasional flicker of tension in Dumbledore's otherwise unreadable gaze.
Then there was Snape.
Their training sessions had grown more intense, more demanding, but beneath Snape's usual sneers and sharp critiques, there was something else. Something Harry couldn't quite define.
And then there was the third-floor corridor.
They hadn't gone near it yet, but a strange pull was in Harry's mind, an itch that refused to go away.
"Did you see the way McGonagall looked at Dumbledore today?" Hermione whispered as they sat together in the library one evening, their books spread out before them.
Neville furrowed his brow. "She looked... worried. Like something was wrong."
Harry tapped his fingers against the table, staring down at the parchment before him. "It's not just her. Snape's been acting strange too."
Hermione gave him a sharp look. "Strange how?"
Harry hesitated. He wasn't sure how much he wanted to share. Their training sessions had become more than just learning Occlumency. Snape had started testing him in other ways—small, subtle exercises that felt like they had a deeper purpose.
"He's just... on edge. More than usual," Harry finally said. "And he keeps asking these strange questions, like he's trying to figure something out but won't say what."
Neville glanced between them. "Do you think it has anything to do with the third floor?"
Silence hung between them.
It was Hermione who spoke first. "We should investigate."
Harry sighed, running a hand through his hair. "We should. But we need to be careful. If Snape or Dumbledore is already looking into it, we don't want to get caught in something bigger than we can handle."
Neville nodded. "Maybe we should see if anyone's been acting strange around that corridor before we do anything else."
Harry smirked. "Since when are you the cautious one?"
Neville grinned. "Since I started hanging out with you two."
The first time Harry noticed Quirrell acting strangely, he almost brushed it off as the man being his usual nervous self. But once he started paying attention, the inconsistencies became impossible to ignore.
It was late one evening when Harry, on his way back from Snape's training, caught sight of a figure skulking near the third-floor corridor. At first, he thought it might have been a trick of the dim torchlight, but then the figure shifted, and he recognized the slight hunch, the trembling hands, and the way the man's turban caught the faint glow of the torches.
Quirrell.
Harry pressed himself against the wall, staying in the shadows as he watched the professor scan the hallway, glancing over his shoulder before approaching the door. His movements were hesitant and cautious, entirely unlike the scatterbrained persona he displayed in class.
For a fleeting moment, Harry considered revealing himself, making some excuse to interrupt whatever Quirrell was doing. But instinct told him to stay put.
The Defense professor hesitated before raising a hand. His fingers twitched, and then he muttered something under his breath. A faint shimmer flickered across the wooden door, like a ripple across still water. Wards.
Harry held his breath as Quirrell carefully traced a pattern in the air. The shimmering glow pulsed faintly before dimming again. Whatever he had been testing, it seemed he was unsatisfied. With a final wary glance down the corridor, Quirrell quickly turned and disappeared into the shadows.
Harry waited a few more moments before stepping away from the wall, his heartbeat loud in his ears.
Quirrell wasn't just nervous. He was up to something.
The next day, he told Hermione and Neville everything.
"You're sure?" Hermione asked, frowning as she tapped her quill against her parchment. "Quirrell was checking the wards?"
Harry nodded. "It looked like he was testing them. Maybe seeing if he could break through, maybe trying to find a weak spot—I don't know. But it wasn't just him being his usual cowardly self. He was methodical."
Neville shifted uneasily in his seat. "What if he's not working alone?"
That thought had already crossed Harry's mind.
Hermione chewed on her lip, clearly running through the possibilities. "It could mean a few things. He might just be checking the protections like any professor would—"
"You don't check a door's wards in the dead of night if you're supposed to be protecting it," Harry interrupted.
Hermione sighed. "Alright, you're right. But that means we have to be careful. If he's trying to get in, we need to know why."
They spent the next few days watching Quirrell more closely. And the more they observed, the more suspicious he became.
He had a habit of disappearing after dinner, always slipping away before most of the staff had left the Great Hall. His stammering worsened when certain topics were brought up.
Like when Dumbledore casually mentioned the castle's security during breakfast one morning. And then there were the headaches.
"I don't think I've ever seen a professor get headaches that often," Neville muttered one afternoon as they sat outside, pretending to study. Across the courtyard, Quirrell was rubbing his temple, his face tight with discomfort as he spoke to another professor.
"Maybe he's under some kind of magical pressure," Hermione suggested. "Or—"
Harry wasn't sure what made him say it, but the words left his mouth before he could stop them. "Or someone else is controlling him."
Hermione and Neville both froze.
"What do you mean?" Hermione asked, her voice cautious.
Harry hesitated. He wasn't sure himself. It was just a gut feeling. The way Quirrell seemed... strained. Like there was something more beneath the surface.
"I don't know," he admitted. "But I think we need to find out."
The breaking point came when they overheard a conversation between Snape and Dumbledore.
Harry hadn't planned on eavesdropping, but when he and Hermione had been returning from the library late one evening, they caught sight of Snape striding toward the Headmaster's office, his robes billowing behind him in his usual dramatic fashion.
Something about his brisk, tense, and controlled movement made Harry exchange a glance with Hermione before they quietly followed at a distance.
They stopped just outside the entrance to the office, pressing themselves into the shadows of a nearby alcove as the voices of the two men drifted toward them.
"The protections have been tested," Snape's voice was low and sharp, barely concealing his irritation. "Someone is probing them, testing their strength. It's only a matter of time before they find a way through."
Dumbledore's voice remained calm. "Yes, I have noticed. And I assume you have suspicions?"
There was a pause. "Quirrell."
Harry tensed.
Dumbledore sighed. "I have been keeping an eye on him. But there is little proof. Do not act hastily, Severus."
"And if he makes his move before we do?" Snape asked, his tone edged with frustration.
Dumbledore's response was softer, more measured. "Then we will be ready."
Silence stretched between them, and then the sound of movement.
Snape's boots struck against the floor as he turned away.
Harry and Hermione barely had time to slip back into the corridor before Snape emerged. They hurried back toward Ravenclaw Tower, their minds racing.
When they found Neville waiting for them in the common room, they wasted no time in telling him what they'd heard.
"So, Snape knows," Neville said, frowning. "But he doesn't have proof."
Harry nodded. "Which means we have an advantage. We can watch Quirrell more closely. Maybe even catch him in the act."
Neville swallowed. "That sounds dangerous."
"It is," Hermione agreed. "But if Dumbledore's watching, that means something's going to happen soon. And if it does—"
"We need to be ready," Harry finished.
For the next several days, they kept up their silent watch, biding their time, waiting for the moment everything would come to a head.
That moment came sooner than they expected.
Because one evening, just as the sun dipped below the horizon, the news spread like wildfire through the castle...
Dumbledore had left Hogwarts.
And someone was bound to act.