a/n: for Tajee165 because she's awesome. Also thank you to Super Cara for pointing out a plot hole (I forget you lot aren't in my head sometimes; really, you should count yourself lucky): I reckon the Head's dorms work slightly differently; because they move around from House to House each year they have a Portrait Hole/password type admittance or when the owner is in the room they can allow anyone access from inside. Any other explanation will do. James is a clever lad.

fifteen – nonplussed

James dumps his bag by the portrait hole, ignoring the yelp of a first-year whose foot he's just crushed under the weight of his backpack, and walks over to his girlfriend's dorm.

He knocks once and leans against the doorframe, also disregarding Sirius' wolf-whistles from across her room. Lily opens the door and he grins at her, and she blinks at him and steps back, allowing him over the threshold.

Lily crosses the room and sits on her bed, sullen.

James is knocked for six. The last time she'd slipped a note into his robe pocket asking him to meet her somewhere it'd been so they could snog in the Runes classroom on the fourth-floor, but there's something in the way she's watching him that tells him she really isn't in the mood.

She clears her throat.

He slips out of his shoes – he knows she hates it when he tracks muddy footprints across her floor – and pads over to the bed, sitting next to her. The mattress squeaks slightly and he looks at her, running his thumb across her cheekbone.

"Are you alright?" he asks softly.

Lily jerks away from his touch and scrambles up on the bed, hugging her pillow.

"Why didn't you tell me?" she asks.

James blinks. Nonplussed: "What?"

"Why didn't you tell me?" she repeats, her tone sharper.

He's wary now. "About what?"

"Oh, I don't know: that you're an illegal Animagus?"

The room is deadly silent apart from the ticking of her alarm clock and the pounding of his heart in his ears.

"Shit," he whispers, and "Lil – Lily -"

She looks at him, jaw set, and he realises how much he's hurt her; it's in her eyes.

"How did you -" he stops, cursing. "Who -"

Lily frowns, unable to speak. And then suddenly, she can't contain it: "Apparently Sirius mentioned it to Remus who felt it his responsibility to apologise and tell me that he was sorry and he completely understood if I never wanted to talk to him again. Naturally I asked what the hell he was talking about and he said, 'You know, Prongs. A stag. You've seen his Patronus, Lily. It's the same.' and I said, 'What's the same?' and he said, 'His Animagus form,' looking at me like I was an idiot."

James rubs a hand over his face and crawls towards her a little more. "Lil -"

"So I said, 'Whose Animagus form?' and he said, 'James,' just like that. So I said, 'James is an Animagus?' and he nodded, and then he realised that I didn't know and he'd just blurted out this whole confession and clapped his hand over his mouth. 'Shit,' he whispered. And then he made me promise not to castrate you." James' eyes snap to hers and he swallows. "I didn't agree," says Lily, and she glares at him.

"Shit," he repeats, sighing. "Lil, I was -"

"Don't 'Lil' me, Potter."

"I was going to tell you, Lily, I was. I promise. I was going to tell you before the next full moon because we've been together for a while and Remus trusts you, clearly – of course I bloody trust you, don't look at me like that – but it's not just my secret to tell, okay? It implicates my best mates as law-breakers. I can't just say that to someone. I can't."

Lily's quiet for moment. Then she closes her eyes and crosses her legs, her chin resting in her palm. "I don't care about the fact that it's illegal or dangerous or incredibly stupid and difficult and such a bloody typical James Potter thing to do, James, I don't, okay? I just – I understand what you're saying, but you lied to me." Lily exhales heavily. "I just don't know if I can trust you anymore."

"What? Lily -"

"James, I have no idea what other things you still haven't told me."

"That's it. I promise. That's the only thing, Lil. No more – what d'ya call 'em? – bons."

She stares at the wall behind his head and bites her lip. "I know I'm over-reacting, okay? I know you were doing it for Remus, and you bloody wouldn't do anything else, would you? I know you couldn't tell me. But none of that makes me feel any better, and I don't want you coming and hugging me and apologising and telling me it'll be okay and that you aren't going to drop any more bloody bombs and calling me Lil. I just need some time to – to get used to it."

James glances at her. "Okay." He budges up tentatively on the bed and stretches his fingers to meet hers.

She looks at him for a long time. Finally, and with a slight smile: "Prongs."

He takes this as acceptance and scoots all the way over to her, wrapping her in his arms. "I'm sorry," he murmurs, lips to her hair. "I wanted to tell you."

Lily leans up and kisses him. "I know. And I do trust you. Really. I do."

She receives a grin in response, and when he kisses her she decides that it is quite impressive.

(She'll never tell him that, though.)