The title is taken from Snow Patrol's Chasing Cars.

It doesn't follow the beginning of 9.23 Do You Believe In Miracles? because I started writing this before that episode aired.


He clenched his teeth together as he lay in bed, not sleeping, letting the darkness consume him. The bunker was silent. Sam had long since left the room, and if he was to guess he'd say that Castiel was probably sitting somewhere, just thinking. As for him, well, he couldn't sleep. He wasn't tired. He was simply... calm.

A narrow beam of light broke the darkness as the door cracked open, and he closed his eyes. It would be better to feign sleep than talk because there were things he shouldn't ask, but wanted to hear the answers to.

The light didn't fade, and if he focused on the back of his eyelids he could see red.

"Dean?" Castiel asked, hesitantly.

Dean blinked and opened his eyes, but said nothing.

After a moment the door started to close, but just before the last sliver of light disappeared Dean sucked in a breath.

"Cas."

The door stopped, then swung further open. Dean counted the footsteps - one, two, three, four, five, six - until Castiel was standing beside his bed. But then, to his surprise, the bed dipped beside him.

"I don't need you to watch over me while I sleep, tonight," Dean joked, but there was no humour in his tone.

"Because you're not going to sleep," Castiel realised aloud. "You can't."

Dean stared at the ceiling.

"Dean..." Castiel breathed, looking around Dean's bedroom as if he was going to find the right words written on his walls. "Why?"

"We needed to kill Abaddon."

"We could have found another way."

"There was no other way!"

"That you know of."

Dean bit down hard on his lip to stop from snapping back at him.

Cool fingers touched the back of his hand lightly, then trailed slowly up his forearm. Without prompting, Dean rolled his arm lazily over. Castiel traced the Mark so lightly, that if Dean couldn't feel the anger resonating off him he could have mistaken the touch for reverent.

"Is this going to kill me?" he asked quietly.

Castiel placed his hand over the Mark. "No."

The breath Dean was holding escaped in a whisper.

"But it will change you into someone you are not. It already is."

Dean said nothing, and Castiel simply sat there with him. Even though Dean's face was in his shadow, Cas could see emotions flicker across his face as he processed his thoughts.

"The Mark is-"

"Would you have done it?" Dean croaked, cutting him off.

Castiel had the decency not to pretend that he didn't know what Dean was talking about. "No," he said, after a moment.

"You didn't sound too sure, then. You wanna try again, without the hesitation this time?"

"No," Castiel repeated firmly.

As soon as Hannah had asked him to punish Dean, he'd known it was over. That he was going to sacrifice everything he'd dedicated himself to working towards. And all because of Dean. All for Dean.

"You're right," Dean whispered. "I'm not gonna sleep. But I'd like it if you stayed anyway."

Castiel folded his hands in his lap and watched him lie there, tense and unable to relax. After a moment Dean shuffled left slightly, giving Castiel more space, and Castiel he realised what it was Dean was asking of him.

Stay.

He removed his trench coat, draping it over the empty chair that sat facing the bed. The tension never left the hunter's body - Castiel could feel it radiating out from his soul, tainted with the darkness of the Mark - but his breathing became less erratic when Cas lay down beside him, hovering as far on the edge of sleep as Dean could manage. Closing his eyes, Castiel let his breathing fall into rhythm with the man lying next to him.

Somewhere in the bunker, Sam was patching Gadriel up as he healed. The trust Sam was prepared to place in the angel was surprising given their history, but then love was known for making humans do things they wouldn't ordinarily do. Castiel was beginning to understand that, now. No matter what Dean did, Sam would always love him. The two brothers would always find their way back to themselves, no matter what tore them apart.

Just as Castiel always found himself returning to Dean.