The next morning, the air in their dungeon office was different. The ghost of the Burrow's inquisition seemed to have followed Hermione down, clinging to her robes. She felt hyper-aware of Cassian's presence, of the space between them, of every quiet breath and rustle of parchment.
He, however, seemed exactly the same—focused, intense, and largely silent. He had a new set of schematics floating in the air, complex runic sequences that twisted and pulsed with a faint, golden light.
"The stasis field isn't uniform," he stated without preamble, not looking up from his work. "There's a weakness. A hairline fracture in the magical matrix. Here." He pointed his wand, and a section of the glowing schematic flared red.
Hermione pushed her personal unease aside, her professional curiosity instantly snagged. She moved closer, peering at the flaw. "A fracture? But you said the magic was flawless."
"The intent was flawless. The execution, over centuries, has developed a stress point. Everything wears down, Granger. Even masterpieces."
The way he said 'masterpieces' sent an unwelcome shiver down her spine. She focused on the schematic. "What's causing the stress?"
"That's the question." He finally glanced at her, his stormy eyes sharp. "It could be a natural decay. Or it could be an external pressure. Something pushing from the outside, or… something trying to get out from the inside."
The implication hung in the cold air. Something alive, trapped and struggling.
"We need to stabilize it," Hermione said immediately, her mind racing through containment spells and reinforcement charms. "If it's a containment vessel, a breach could be catastrophic."
"Stabilize it, or understand it?" Cassian countered, a familiar challenge creeping back into his voice. "We could use the fracture. Thread a probe through it. A tiny, non-invasive thread of magic, just to listen."
"That's too risky! We don't know what's on the other side. We could aggravate it. We could rupture it completely!"
"Or we could finally get an answer!" he shot back, turning to face her fully. "We've been circling this thing for weeks, Granger. Listening to its heartbeat, reading its sad stories. It's time to ask it a question."
"This isn't a conversation, it's a surgical procedure on a comatose patient! You don't just start poking around in the brain!"
"Why not?" he demanded, his eyes flashing. "If it's the only way to understand the sickness? To maybe, eventually, help it?"
"Help it? Or satisfy your own curiosity?" The words were out before she could stop them, sharp and personal.
The air went still. Cassian's face closed off, the brief flash of passion replaced by a cold, hard mask. The connection they had forged in the dark, the understanding over lunch, it all seemed to evaporate in the face of her accusation.
"I see," he said, his voice dangerously quiet. "So that's what you think this is. That I'm just a reckless thrill-seeker, playing with forces I don't respect."
"I didn't say that," Hermione backtracked, her chest tight.
"You didn't have to." He turned his back on her, dismissing her. "Go on, then. Write your report to Shacklebolt. Recommend a full containment protocol. Wrap it in so many layers of bureaucratic caution that no one will ever dare look at it again. That's your solution to everything, isn't it? More rules. More control."
The comment cut deeper than it should have. It echoed the old, childish taunts from her school days. Insufferable know-it-all.
"That's not fair," she whispered, her voice thick.
He didn't reply. He just stood there, a rigid silhouette against the humming Vault, the fracture in its magic mirrored by the sudden, painful fracture in their fragile partnership.
Hermione felt hot tears of frustration prick her eyes. She wouldn't cry in front of him. Not again. Not like this.
She turned and walked out, her footsteps echoing in the silent chamber. The heavy door swung shut behind her with a definitive thud that felt like an ending.
She didn't go to the Ministry. She went to the one place she always went when her mind was in turmoil: the library. But today, the towering shelves of books offered no comfort. They felt like a cage. Cassian's words echoed in her head. Wrap it in bureaucratic caution… That's your solution to everything.
Was he right? Had she become so focused on safety, on procedure, that she'd lost her nerve? The girl who had broken into Gringotts and ridden a dragon to freedom would have leapt at the chance to thread a magical probe into the unknown. That girl was buried under two years of grief, responsibility, and the weight of being a "War Heroine."
She thought of his face when he'd talked about the Vault's grief. There had been no thrill-seeking in his eyes then. There had been a profound, almost painful empathy. He saw a wounded thing, and his first instinct wasn't to cage it, but to understand its pain.
Maybe she had been wrong. Not about the risk, but about his motives.
Sitting alone in the silent library, Hermione Granger realized the most terrifying risk wasn't the magical fracture in the Vault. It was the one forming in her own carefully constructed world, a crack caused by a man who challenged everything she thought she knew about magic, and about herself. And for the first time, she wasn't sure if she wanted to seal it shut or let it break open.