Disclaimer: I do not own BBC Sherlock

Warnings: None

When Jim worms his way into Sebastian's bed his hands and feet are like ice brands; for once Sebastian is the one with the body heat. With every slight touch of Jim's hands, and every little prod of his toes against his calves, Sebastian jolts instinctively, trying to recede back into the den of sleep and heat.

He knows what has happened, but didn't hear Jim's yell for help as he awoke from his nightmare; it must have been a silent cry. Jim's sneaking into his bed would have been perfectly silent too if Seb wasn't trained to detect the slightest of sounds; every footstep, every breath.

He lies begrudgingly awake in the dark, trapped against the equally icy wall, now unable to pull any further away from the small and chilly body curling around him. He doesn't say anything, because he's not allowed, not supposed to. It's their unspoken agreement; Jim has a nightmare, Jim climbs in, Sebastian shuts up, they go to sleep, Sebastian wakes up, and Jim has gone.

He feels the cold press of Jim's nose in the join between his neck and shoulder, and the ghost of his breath tickling his skin, still fast and uneven. Carefully, inch by inch, he moves so that Jim settles into his side, resting in the crook of his arm.

Sebastian follows the moonlight, lets his gaze fall on the shadows on the ceiling. He tries to make his mind conjure them into scathing creatures with talons and teeth, or evil strangers, or phantoms of a bad past or whatever the hell it is that Jim sees.

To him they're just the shadows of trees and bare branches, throws of moonlight blocked by curtains and unthreatening objects. I can't put a bullet in what I can't see.

Jim's breathing falls, settles into a calm rhythm, and Sebastian tries to get used to the warming body against his and the still icy feet tangled about his legs. He attempts to get back to sleep, though it's difficult now he knows Jim's night hasn't been as comfortable as his own. He's struck with a powerful sense to guard, to just lie awake and somehow protect him from invisible things.

As he begins to drift off involuntarily, Jim begins to stir again, arching his body, trying to curl up, heart speeding in his chest again. Sebastian presses his lips to his sweat-beaded temple causing him to unfurl and relax. He breaks their rule, uttering a sound.

"Shh…"

Jim simply sleeps peacefully again.

Day is always such a contrast to the night. Jim is such a contrast. Perhaps they both are. That very morning Sebastian had been armed and dangerous, fresh from the hunt, an air of aggression and power still lingering with his cigarette smoke, and James Moriarty had whipped through the corridor, shoes clicking sharply on the polished floor, a finely tailored devil barking into a phone.

"No, no, no, you're not LISTENING to meeee…." His voice had been a broken note, resounding through the halls, and Sebastian had pictured his eyes under his shades, treacherously black.

But by late afternoon, when they had finally retired for the day, Jim's voice had fallen to a lazy rich drawl as they lounged in the living room sharing alcohol.

"You don't usually drink with me," Sebastian had pointed out casually, leaving out the fact he'd like it to happen more often. Jim was good company when he was languid.

"Tiger, Tiger…" Jim had purred over the sound of their colliding glasses, "I don't usually take the liberty of explaining myself to you either. That isn't about to change…"

As he settles into sleep, Sebastian wonders when the bridge appears and Jim crosses into a reality that he hates, full of things only he knows of. He wonders if it's only at night, or if there were shadows clawing at his chair and invisible strangers walking through the room that very afternoon as they sat together.

He's awake again in the early hours of the morning, birds shrieking in the trees close outside, and damn if he doesn't want to aim a rifle out of the window and fire.

Jim is the first thing that comes into focus as daylight pierces in, still asleep, still there, brow softly furrowed. His hands are balled into fists and gripping handfuls of Sebastian's shirt. They've both broken the rule now and so no one's to blame, Sebastian decides, reaching out and smoothing down the ruffled dark hair until the frown has disappeared and he feels the hands release his clothing.

Still, he shuts his eyes and feigns sleep, awake all the while, even when Jim gets up and walks out as if Sebastian and the contents of his room no longer exist. It's easier for both of them to believe the rules are still intact.