The walk back through the sleeping castle was different. The silence between them was no longer a wall, but a companionable, thoughtful thing. They didn't speak, but the air wasn't heavy with unsaid arguments. It was filled with the echo of his smile and her admitted respect.
At the entrance to the Headmaster's—Headmistress's—office, the stone gargoyle stood silent guard.
"I'll, uh… I'll see you tomorrow," Hermione said, feeling suddenly, unaccountably shy.
Cassian nodded, his hands shoved into his pockets. The casual gesture was so at odds with his usual precise posture. "The deceleration should bottom out around 2 AM. I'll have the data for you in the morning."
"Right. The data." She clutched her bag a little tighter. "Goodnight, then."
"Goodnight, Granger."
He turned and walked away, his footsteps echoing softly down the corridor until he turned a corner and was gone. Hermione stood there for a moment longer, the word "Granger" sounding different in her mind. It had lost its sharp, dismissive edge. Now it was just… her name.
The next few days settled into a new, strange rhythm. The professional rivalry was still there, a fundamental part of their dynamic, but its edges had been sanded down. They debated methodology with less venom and more genuine curiosity. He would present a theory based on his intuitive readings; she would counter with a historical precedent or an arithmantic proof. It was no longer a battle for dominance, but a collaboration, a fitting together of two different halves of a puzzle.
One afternoon, while they were taking a late lunch in their temporary office—a cramped room near the dungeon that smelled of old parchment and damp stone—the conversation strayed, for the first time, from the Vault.
"It's the intent that's the key," Cassian was saying, gesturing with a turkey sandwich. "The stasis isn't a cage. It's a… a blanket. A comfort."
"To soothe the grief you mentioned?" Hermione asked, sipping her tea.
"Exactly. It's not about suppression. It's about preservation. Keeping something precious safe, even if that something is pain." He took a bite of his sandwich, chewing thoughtfully. "It's a more sophisticated piece of magic than anyone at the Ministry gives it credit for. They just see a locked box."
"They see a potential threat," Hermione corrected gently. "It's their job to."
"A threat can be beautiful," he said, his gaze distant. "A lightning storm is a threat. The ocean is a threat. It doesn't make them any less magnificent."
She looked at him, this man who saw magic not as a tool or a weapon, but as a living, breathing work of art. It was a perspective that was both thrilling and terrifying.
"You never trained as a traditional curse-breaker, did you?" she asked. "Not like Bill Weasley."
He shook his head, swallowing his food. "No. I was… recruited. Straight out of Hogwarts. The Department of Mysteries doesn't care about N.E.W.T.s. They care about how you see the world. How you listen to it."
"Hogwarts? What house?"
He gave her a sidelong glance, a ghost of his old smirk returning. "What do you think?"
She didn't even have to think. "Ravenclaw."
"Obviously," he said, and there was no arrogance in it, just a simple statement of fact. "You?"
"Gryffindor," she said, and for the first time in years, she didn't feel the need to justify it, to prove she belonged there despite her bookishness.
"Also obvious," he replied. "The moral courage is… loud."
She wasn't sure if that was a compliment or an insult. "What's that supposed to mean?"
"It means you can't see a problem without feeling compelled to fix it. It's very… exhausting to watch." But he said it without malice, almost with a hint of amusement.
Before she could retort, the door to their office opened and Ron poked his head in, his face breaking into a grin.
"There you are! I've been looking all over for—" He stopped, his eyes landing on Cassian, then on Hermione, then on the two of them sitting at the same small table, surrounded by scattered notes and half-eaten lunches. His grin faltered for a fraction of a second, replaced by a look of pure, unadulterated surprise.
"Ron!" Hermione said, a little too brightly. "What are you doing here?"
"Just dropping off some reports for the Auror office," he said, stepping fully into the room. His eyes were fixed on Cassian, who had put his sandwich down and was watching Ron with a cool, neutral expression. "So. You're Thorne."
Cassian gave a slow, single nod. "Weasley."
The air in the small room suddenly felt thick. Ron's protective, brotherly aura was practically visible, a shimmer of red-headed concern. Cassian's stillness felt like a challenge.
"Ron, Cassian and I were just going over the night-cycle data," Hermione said, trying to defuse the tension. "It's fascinating, the resonance actually—"
"Right. Fascinating," Ron interrupted, not taking his eyes off Cassian. "Listen, mate. Hermione's like my sister. You treat her right, yeah?"
"Ronald!" Hermione hissed, her face flushing with embarrassment.
Cassian's lips twitched. Not quite a smile. He looked from Ron's earnest, frowning face to Hermione's mortified one.
"Your concern is noted, Weasley," he said, his voice dry as dust. "But I assure you, our collaboration is strictly professional. Granger is more than capable of handling herself. She's already corrected my arithmantic calculations twice this week."
Ron blinked, thrown off balance by the response. He looked at Hermione, who gave him a small, tight smile that she hoped said, Please leave now.
"Right. Good. Okay, then," Ron said, shuffling his feet. "I'll, uh… I'll see you at dinner, Hermione? At the Burrow? Mum's asking."
"Yes, of course. I'll be there."
With a final, suspicious glance at Cassian, Ron left, closing the door behind him.
The silence he left behind was deafening.
Hermione let out a long, slow breath. "I am so sorry about that."
Cassian picked up his sandwich again. "Don't be. It's… quaint." He took a bite. "Loyalty. Another loud Gryffindor trait."
She couldn't tell if he was mocking her or not. "He means well."
"I'm sure he does." He finished his sandwich and stood up, brushing the crumbs from his trousers. "I need to check the baseline readings. Don't be late for your… family dinner."
He left her sitting there, surrounded by the evidence of their shared work, the ghost of Ron's protective interruption hanging in the air. The shift was undeniable. The outside world had intruded, and it had seen them not as warring colleagues, but as two people sharing a quiet lunch. And the most unsettling part was, for the first time, it didn't feel entirely wrong.