The locked door becomes a new norm. Hermione whiles whole mornings away watching September slip almost imperceptibly into October through the glass panes of their small kitchen window, imagining herself into crowds and markets and diners that serve watered-down coffee. She misses it all.

Snape, in turn, disappears behind the door more and more, only coming out to work, otherwise self-sequestered with the aid of his mysterious lock. They rarely even eat together anymore; he takes his meals in his room at strange hours and consumes so little that Hermione, even in the midst of her irritation, becomes increasingly concerned for him and his wellbeing. He speaks to her even less, if that's possible, but does continue to leave dutiful and detailed notes in the lab notebook, so she has no real reason to complain. He isn't sleeping, she notices. His face, on the rare occasions she sees it, is drawn and pale. The circles beneath his eyes have become a deep violet.

Days pass without a reason to use her voice. The two of them go whole day-long periods without even seeing each other, which strikes her as something of a feat considering the size of their shared space. She finds herself missing their previous collisions, every now and then even yearning for the kind of intrusion she used to despise and dread.

She begins to speak out loud to herself, mostly in her bedroom, curled up with one of the many books on her host's sprawling shelves. She reads the stories aloud to remember what her voice sounds like. The composition of beautiful sentences, nouns and verbs and all their modifiers.

There are a handful of mornings she wakes and warms her fingers around a mug of hot breakfast tea, then carries it from the kitchen into the hall and stands outside of his door. Just gazing at it, her eyes slipping into an unblinking trance as she considers the worn white wood that separates them. And it occurs to her, gradually, that she wants to speak with him. In the strangest and most unimaginable turn of events she has begun to miss her conversations with Severus Snape. For now she'll chalk it up to a side effect of extended self-isolation. Once she goes so far as to raise her hand to the door, but for whatever reason Hermione can't bring herself to knock.

One night there's a fire.

She'd started a new recipe on her own that morning, trying something not in any book—a potion of Snape's own devising, yet untested, intended to jumpstart the respiratory system and reinvigorate the lungs.

But she notices early on that the flames beneath the cauldron are behaving strangely. For one thing, they begin to change colors. Out of the corner of her eye she thinks she sees an infinitesimal shift from the usual mild orange to a bright, lurid green. And every now and then she adds ingredients and jumps back with a start as fire licks up the sides of the cauldron, crackling closer and closer to her fingers, once almost singeing her hair.

Hungry. That's the word that comes to her. The fire seems hungry. In fact she actually walks all the way upstairs and down the hall to Snape's bedroom, but again she sees the brass lock on the door and thinks, stupid girl. That's what he'll call me if I knock. I'm so out of my mind with loneliness that I've begun personifying a fire to keep me company.

So she goes back downstairs, and a few hours later it happens.

She is quietly taking notes when a sudden strong heat beats heavy at her back, followed by a loud pop. She spins to see the fire has gotten loose from the enclosure beneath the cauldron. It burns quickly across the floor toward her like a snake, twisting closer. Moving as if it can see her, like it wants her. A dangerous, pulsing green.

In an instant, her path to the stairs is already obscured by the flames.

No time to think. But she must.

Hermione looks around wildly. The flames lick dangerously close to the worktable; the room is filling with smoke so dark green it's almost black. Trying not to inhale, she grabs the notebook and clutches it to her chest. The smell is so strong that she can almost feel it on her hands and skin, surging up through her nostrils and inside her mouth, threatening to suffocate her. An odor like rotting fish, burning flesh—like death.

The scariest thing is that she doesn't just see and smell and taste the fire—she can hear it, too. The conflagration only gets louder as it expands with a crackling and the sound of wind. Worse, it seems to have a mind of its own, jumping about the room as if targeting specific objects. Like no fire she's ever seen.

The cauldron—their solid, indestructible cauldron—appears to be melting.

Suddenly she remembers—idiot, she thinks—the self-filling bucket of water resting beside the worktable expressly for this purpose. In case of emergencies, Snape had said. Still gripping the notebook to her chest with one arm—unthinking, unable to let go of it—she heaves the pail up by its thin metal handle and tosses its contents at the now-raging flames.

The fire only burns stronger. She gasps as it consumes the water—impossibly, like a kind of fuel—and advances further. Like it wants more.

Fear, Hermione realizes. She backs into the far corner, next to the shelves of ingredients. Fear is what she's feeling. She hasn't felt anything so viscerally in years.

There's no way out. Smoke obscures most of the room, like a cage around her.

She throws herself at the shelves beside her and claws at any bottle of liquid, desperate for something that might help. The ingredients blur together; in her panic she can hardly read. Fragments jump out at her. Venom. Blood. Wings.

The flames are destroying everything—he'll be so angry if he discovers her like this, she thinks—she's failed unless she can stop it. She grabs vials and jars at random and throws them at the blaze, knocking things over in her haste, tears streaming from her eyes. Honeywater and pumpkin juice and all their home-brewed antidotes. She throws them all. Glass shatters in the flames and all around her. She feels it crunching beneath her feet.

But the fire leaps closer still. It starts in on the far side of the shelves, beginning to lick up everything in its path. Something on the shelf explodes. The smoke is completely black now. She can barely see anything outside of brief shocks of green light as the fire jumps and moves, and the room is so hot now she has no words in her to describe it.

A racking cough overtakes over her. She doubles over, unable to breathe, unable to fill her lungs despite great gasps for air that cut through her chest like blades. Every breath fills her with smoke. Her hand scrabbles blindly on the shelves to her right, but there's nothing left to throw.

Pain shoots up from her knees and radiates through her thighs—when did she fall? She tries to stand back up, but the heat hits her like a mallet, forcing her back down again. The smoke is so dark and all-consuming at this point she can't tell if her eyes are open or closed.

Her lungs are paralyzed, decimated.

There's no air left to breathe.

She feels herself succumbing.

But then she hears a roar over the blaze, louder than it.

Later she'll wonder if she heard him at all. If perhaps he didn't speak directly into her mind. The most familiar syllables she knows:

Hermione.

He's never called her that before.

Hermione.

Her body is calling her to sleep, to escape into cool darkness. Butt there's a part of her that listens and lingers.

Who is that?

Hermione, where are you?

She parts her cracked lips to answer out loud and smoke fills her mouth like a fist. She heaves a wordless, animal cough.

Through a dark wall of smoke he appears before her, as if summoned by the depth of her need. Great streams of light shoot from his wand, filling the room with white that filters through the smoke—drenching it, dispersing it, like a bright, intangible liquid. Blearily, eyes streaming, she observes that the magic looks like water but moves like wind as it surges all around them.

What spell? she wonders hazily. Why didn't I know it?

Snape kneels beside her; she registers the chafe of his bent knees against her ribs. She seeks out his face but is too exhausted to decipher the expression she finds there. His eyebrows are knit together, forcing a single wrinkle in between.

His hands quickly push the notebook from her chest and then push into her lower ribcage, beneath her breasts. She twists her head to the side, looking around him, trying to see what's happening in the rest of the room. She can't see the fire anymore, can't hear it either. The smoke seems to be evaporating despite the room's lack of ventilation, revealing enormous scorch marks like great black gashes on every surface. The shelves are half-gone, the oak and the things it held reduced to velvety piles of ash.

She again registers a weight on her chest, looks down. He's murmuring something now, pressing his fingers into her torso so hard she can feel the pressure inside her lungs. Then there's a loosening. She heaves, gasps for air. She has to tell him.

"S-saved book," she says. She can't lift her hand, so she points to the floor where he pushed it. An aureole of light tunnels her vision, almost obliterating his face from view. She fights it back, tries to focus on his dark eyes. "Sn-Snape—I don't know what—we—we need to—"

"We need to get you out of this room," he says bluntly. "You're going to asphyxiate if you remain."

She feels his arms move gently from her torso to slide beneath her body. She resists, twisting against him as he begins to lift her.

"W-wait—the fi-fire—" An attack of coughing cuts her off.

"I took care of it, Granger."

"Wasn't nor-normal—you have t-to tell me what spell—"

He ignores her and she registers a sudden upward movement, a rush of air around her calves and through her tangled, soot-black hair. Her head rolls automatically against his chest and lolls there in the crook of his elbow as he ascends the stairs, holding her. The urge to faint is overwhelming, as if her body requires unconsciousness in order to process the physical trauma it just endured. But she has to know their book survived, that its pages are still legible. She has to know the last three months weren't undone in just a few moments.

Why didn't she see this coming? Why couldn't she stop it?

"I-I'm s-sorry," she coughs, her throat coarse, vocal chords aching, chest heaving. But Hermione has to say it.

Her eyes finally slip shut. She still vaguely senses his movement, the steady beat of his footsteps up the rough stone stairs and then a rush of cooler air as the heat finally begins to dissipate. The smell of smoke is still everywhere; she coughs again and feels soot in the back of her throat, on her tongue, in her eyes, soiling her hair and sinking into her scalp, filling her lungs, even settling between her teeth, in her gums. She'll never get it all out.

Now there's something beneath her again, but softer than the ground, more stable than his hands. She sinks into it, her mind finally allowing itself to unspool.

"Why didn't you call for me?" she hears, as if very far away, but she's falling, falling already, so fast.

The voice cracks.

"Did you think I couldn't save you?"

She comes to in a heap of blankets on Snape's bed. He sits in a wooden chair to her left, illuminated only by an odd sliver of light that streams through the cracked door of his wardrobe. He sits back in the chair as she stirs, blinks herself awake.

"Per recent circumstance, Granger, I must inform you that you're no use to me if you're dead."

Her body aches all over—her head and chest especially. Every breath cuts. She tries to breathe shallowly, which offers slight relief.

"That wasn't a normal f-fire." Her voice surprises her. Rough, yet weak.

"Correct."

He's still covered in soot, she notes blearily—his face, his hands, his clothes—and the whites of his eyes are shot with red, likely from the smoke. She wonders what she must look like. He stands up and begins to pace the length of the small space as he continues.

"Cursed fire, Granger. Nature senses what we're trying to do, and—corrupted by our effort—fights back." He stops at the foot of the bed. "As I'd previously informed you, you were never supposed to begin one of my own recipes without my immediate presence. It's simply too dangerous to undertake on one's own. It is, in part, why the Ministry mandated I begin working with an assistant in the first place. Last time…" He pulls unthinkingly at his sleeve, stares off into space somewhere above her head. "Last time, an incident much like this occurred."

He looks down sharply, as if only just remembering why she's in his bed.

"Are you in pain?"

She contemplates lying, but groans involuntarily as a white-hot beam shoots through the center of her head, forcing her eyes closed.

"That's a yes, then," she hears him murmur. When she opens her eyes, he is gone. A moment later the floorboards creak and he's before her again, holding a smoking mug. She reaches out hopefully, thinking it's the Dreamless Sleep potion she's come to crave, but pushes back against the ceramic reflexively when an acrid stench reaches her nose, releasing a small moan of disgust.

"If you don't drink it, the pain will be far worse."

He pulls back momentarily, but his tone carries a warning note that sways her.

"Fine," she says in what she hopes is a stronger voice. She holds her breath as she swallows it down, Snape standing over her watchfully in a way that reminds her of Madam Pomfrey, years ago.

He takes the mug back and is just turning to leave when Hermione opens her mouth, forcing the words out before she can change her mind.

"If this is nature's response…" she swallows. It's painful. "Maybe it's not right. Maybe we should stop."

As is so often the case when she says something Snape disagrees with, he simply ignores the suggestion entirely.

"You should've had your wand. That's the only thing for it, and I refuse to indulge your resistance any longer. Before we continue I fully intend to reintroduce you to, at the very least, rudimentary spellcasting, since you appear to be incapable of handling the task on your own time."

Framed in the doorway, he turns and surveys her impassively.

"I'll draw you a bath, Granger. You seem to have quite a taste for them."