Disclaimer: I don't own Supernatural or any of these characters.

A/N: A quick one shot that's sort of a head canon of mine. I'm rewatching season six and I think the Cas/Dean relationship is so complicated and aghh, I love it. :3 I don't have a specific time for this piece, just around mid-way through season six, before they know Cas is working with Crowley.

Our Four Hours

Dean needs his four hours.

Cas would repeat this to himself on the nights he stood guard over Dean.

Castiel didn't know how Dean slept before he was in Hell. It was difficult to know what was a side effect of his time in the Pit and what was merely a product of his upbringing.

If Cas had taken to watching Dean sooner, he'd have seen him snuggled into Cassie, as though they were sharing skin, their legs and fingers and hair all intertwined.

He would have seen Dean as a child, pulling Sam out of his crib and cradling him on the floor of his nursery when the two were supposed to be taking separate naps.

He would see the countless women who took up residence for a night, or maybe two – a week, at most – next to Dean, the delicate intricacies of a relationship between strangers pouring into their body language through awkward poses and numb limbs.

He would see Dean forgoing sleep, as he watched over his grown-up little brother, too scared by Sam's secrets to sleep.

When Dean slept with Lisa, they slept on opposite sides of the bed. It was no indication about his feelings for her, because he loved Lisa as much as he thought he could. But his four hours were different now. The intimacy of sleeping next to someone was a luxury Dean couldn't allow himself anymore.

There were times, of course, when exceptions were made. Mostly it was in the early morning hours, when Dean would lie in bed, alert and still from his four hours of sleep. He would lift himself to the other side of the bed in one giant motion, careful to not wake Lisa. He would breathe in the smell of her cinnamon shampoo and drape an arm around her protectively.

She would wake to him on his own side of the bed.

Cas didn't like to stay too long during those moments. Dean couldn't see him, naturally, but it felt…invasive – a concept that was unfamiliar to Cas and made him feel guilty when he'd replay the scenes in his head later. He didn't really understand why – he was doing nothing wrong; he was watching over Dean to make sure he was safe. He knew that Dean wouldn't see it that way, though, and that these were moments Dean would certainly wish to be private.

Of course, Castiel had plenty to feel guilty about these days.

Bringing Sam back. Leaving Sam's soul in the Pit. Ignoring Sam's prayers.

He'd done it all for Dean. It all just kept going wrong.

Some nights, after Lisa had vacated the space next to Dean, when the guilt would overwhelm him, Cas would stand guard the whole night. He got to know the ways Dean's body would spread across the lumpy motel mattresses.

If his nightcap was a double, he would pass out face down, limbs spilling over the edges of the bed.

If he was thinking about Lisa, he slept on his side, his arms in front of his face and wrapped tightly around the pillows meant for a partner who should be sharing that space with him.

If he couldn't sleep – and there were many nights when he couldn't manage even his meager four hours – he would sit up against the headboard, his back straight and eyes forward, a quiet scowl drawn across his face.

But the nights that were particularly painful for Cas were the nights when Dean thought of Hell. Torture in Hell, Dad in Hell, Sam in Hell, Adam in Hell – Dean's guilt coupled with his own memories of the Pit, causing him to trash wildly. The display was silent, aside from the thwacks and thuds against his mattress, making the whole thing incredibly disturbing.

Cas would watch and he would want to intervene.

He was the one who brought Sam back without a soul. He did this. He pulled Dean out of that bed with Lisa and those private, intimate mornings and dropped him into a world where his nightmares paralleled his reality.

When the thrashing finished, sometimes Cas would sit on the edge of the bed and wait for Dean to wake. He would wonder if Dean could sense him somehow. It was absurd, for Dean possessed no psychic abilities and didn't practice any sort of magic, at least not magic that wasn't purely defensive, so obviously Dean couldn't sense Cas, at least not really. But sometimes Cas thought he could feel Dead pulling for him, even when Dean wasn't praying to Cas. The extent of their bond was fuzzy overall.

If too much time passed after the nightmares calmed, Cas would reach out for Dean. He'd pause before grabbing Dean's hand – he was sure that if Dean were awake, the gesture would make him nervous – and sometimes he found that Dean was shaking underneath his skin. He'd want to wake him. He would want to climb into the bed next to Dean and hold him the way Dean used to hold Lisa. And then he'd want to wake Dean and cry about how sorry he was; how truly, truly sorry he was for ever dragging Dean into this.

These were the closest thing to dreams that Cas had.

Dean needs his four hours.

I'm so sorry.

Dean needs his four hours.