A/N - Written for the What a Boyfriend should do Competition on the HPFC forum, with the prompt "When she looks at you with doubt, back yourself up."

By Moonlight

"You've got an invisibility cloak?"Lily asked incredulously as the silvery fabric slid smoothly from James' bag.

"Impressed, Evans?"

"Not really. Here I was, thinking that all those times you'd managed to get yourself out of trouble over the years were through some actual skill, but you've been cheating all along."

James gave her a mock wounded look, before diving under the cloak and disappearing before her eyes.

"Who needs skill when you've got one of these? Effective, isn't it?"

"Except when worn by an arrogant prick who can't stop talking." Lily lunged playfully in the direction of James' voice and felt her fingers just brush against the silky fabric, as he dived out of the way.

Silence fell for a few seconds.

"Alright, James, you can stop messing about now."

There was no answer. The darkened, deserted corridor began to feel a little eerie.

"James?"

"Ja-AAARGH!" Lily screamed as her boyfriend's face appeared suddenly less than an inch from her own.

"Merlin, Lily, what are you doing screaming like that? I thought you didn't want us to get caught," James scolded, unable to keep the laughter out of his voice. "There's bound to be someone coming now. What will they say when they see perfect Lily Evans-"

"You absolute bastard, Potter," Lily hissed, driving her fists into his chest. "You let me under that cloak right now!"

"Well that's not very polite now, is it?" James asked, but at the sound of approaching footsteps, he held the cloak out to cover them both and held her against him, as Filch limped angrily along the corridor in search of the source of Lily's scream.

"So what is it that's so important you had to drag me out of bed at one in the morning?" Lily whispered once the caretaker was out of earshot. She expected another joke or some glib comment, but to her surprise, James seemed to stiffen a little and his smile faded.

"Come on," he muttered and with an arm around Lily's waist, he walked her out of the castle and onto the grounds.

"I'm pretty sure you don't have to hold me quite so close to you," Lily teased.

"Of course I do, otherwise the cloak wouldn't cover us both," James replied with mock innocence, though Lily still could not help the niggling feeling that something was bothering him.

"So that's how it works is it? Should I be worried about you and Sirius cosying up under here?"

James smiled but did not reply. There was definitely something wrong. He seemed almost nervous but she couldn't think why that would be. He had spent more time roaming the grounds after hours than anyone else at the school.

He led her around the lake, which rippled silently under the silvery light of the crescent moon. Lily's own experiences of the Hogwarts grounds after dark were very limited, but it was not the eerie, forbidden landscape she had imagined it to be. The spring air was crisp, but not cold, and with James' warm body next to hers, the stillness seemed peaceful, almost comforting.

At last they stopped at a patch of shore shielded from the castle by great weeping willows whose branches skirted the water's edge. As James shrugged the cloak from their shoulders, Lily realised that she recognised the place as somewhere they had come a few times in the autumn, when she and James had first started going out, before the weather turned colder and the days became too short for sitting outside in the afternoons to be a good idea.

James laid the invisibility cloak out like a blanket on the grass, where it shimmered prettily in the moonlight.

They sat down and looked out across the lake.

"Lily, I wanted to talk to you," James began stiffly. "It's about what we're going to do after we leave here."

Lily blinked up at him. They had discussed this so many times before. "We're going to join Dumbledore and fight, James. We have to. Are you having doubts?"

"No, no, it's not that. It's just-"

"James, are you having doubts about... me?"

"No. I..." He trailed off. She had never seen him looking like this, so unsure of himself.

"I want you to marry me," James blurted out.

There was a long silence.

Lily began speaking in voice that seemed far higher pitched than usual. "We shouldn't rush into something like this, it's not, it doesn't seem sensible. We've only been together six months, how can you even be sure?" She looked up at him doubtfully.

"I'm sure. I know people will say that we're rushing into this but I've been sure about you for a long time. And yes, maybe I wouldn't be asking this if there weren't nutters who're going to try and kill us as soon as we leave school, but I'm still sure I'd be asking at some point. So if you're sure too?"

"Yes, I think I'm sure."

"That doesn't sound very sure," James said with a flash of his usual smile.

Lily smiled too. "I know I'm sure."

James wrapped his arms around her tightly. "I got you a ring and everything."

"Merlin, James, how long have you been planning this?"

"A little while."

"Who knows about it?"

"Oh. No one. Just in case you said no." He passed over the little leather bound box from his pocket and the ring within it gleamed in the moonlight.

"It's so beautiful," Lily murmured. "Thank you," she leaned in closer towards James and pressed her lips to his.