Castiel sat in a motel room on a Tuesday night. He's been out hunting with them again tonight, Sam and Dean. Or, well, they had a lead, but it turned out to be dead. They never found anything worth going after, but even so, Dean was exhausted when they got back here. And so, Dean fell asleep on one side of his bed, lying on his side, arms wrapped around the extra pillow. Sam had fallen asleep on his back, with his head turned to face the wall. He slept on one side of the bed as well, though that was most likely a habit still stuck in him after spending such a long time with someone. Even though that's long ago, his past with someone else than Dean still shines through from time to time.

Castiel had been sitting in this chair for hours, now, watching Sam and Dean. Listening to their soft, and sometimes not so soft, snoring. Their steady breathing and light snoring brought peace to his mind, and he was able to sit back and relax for a little while at a time until a loud snore would cause him to start.

Keeping his eyes on the boys, but letting his mind wander, his eyes settled on Dean as he wondered how he had become as lucky as to have his life entangled with someone like Dean's. How he regretted nothing he had done, or Dean had done, or Sam had done, or anyone had done, because all of it lead to this. All of it had lead to him depending on the Winchesters, and the Winchesters depending on him, even if it had taken a while. He wouldn't give this up for anything in the world.

Just then, Dean stirred, slowly waking up, and after a moment looking over in Castiel's general direction. "Cas," he said. His voice was groggy from sleep and his eyes were barely open. His shoulders and back were a little tense. "You still here?" He couldn't see anything in the dark. The blinds were drawn, shutting out any moonlight that would have come in otherwise. The room was in total darkness for anyone but Castiel.

"Yes, Dean," Castiel said. He watched as the tension in Dean's shoulders and back melted away a little, and Dean relaxed back into the mattress. "Would you like me to stay, or would you prefer if I left?" he asked. He couldn't help it; he wanted to know. He watched Dean tense up a little again.

"Whichever is fine," Dean said after a moment of silence.

"I'll stay for a while, then," Castiel said. Dean didn't answer him; just relaxed into the mattress again, and it wasn't long before Castiel could hear his breath slow – he had fallen asleep again. When he was absolutely sure Dean was asleep, he whispered four words, barely loud enough that Dean would have heard it had he been awake. "I made a promise."

Being reminded of that promise, Castiel decided he would have to go tonight. He wanted to go. He had only ever gone once, but it was a thought that had caught his attention many times more. An idea that had almost left him breathless whenever he would come to think of it. So he got up, leaving the room, making sure the door is locked behind him. He briefly wonders why he bothered with the door.

He's feeling a little bad for leaving after he told Dean he'd stay, but he pushed the thought away. It's not like he'll know.

Castiel is walking up to the Winchesters' house on May 15th, 1979. It's earlier on the year than the last time. She won't know him. When he knocks on the door, a moment passes, but then Mary Winchester is standing in front of him. She has a baby in her arms – Dean. He's crying, and Mary looks like she's about to give up.

"I'm sorry, John isn't home, and I can't-" she starts, but Castiel speaks before she finishes her sentence.

"Good," he says. "It would be rather unfortunate if you would have to explain your background as a hunter to him simply because I showed up. That is not what I wish."

"What?" she asks, staring at him in surprise and slight panic. "How do you- oh. You're one of the angels from last year, aren't you?"

Castiel was sure he'd cleared that episode from her mind. It doesn't matter. "Yes," he says.

"John doesn't remember," she says, as if that's what Castiel is so worried about. It's not. Dean's crying is getting louder by the second, and Mary sighs as she looks at Dean briefly and then back at Castiel. "Please come in. I can't have him bothering the neighbors like this, and he won't stop crying."

Castiel nods and follows her inside. They go into the nursery, and Mary stands by the window, looking outside. Castiel stays in the doorway, watching her with Dean. "Does he cry like this often?" Castiel asks her. He can't help but want to know more about Dean, even as a baby.

"No," she says. "Never. He's usually so quiet and calm."

Castiel nods. "Would you like me to give it a try?" he asks. "You could go and rest." It takes a bit of coaxing, but eventually, Castiel stands with baby Dean in his arms. Dean is wrapped in a piece of fabric Castiel doesn't know what is, and beneath it he's wearing clothes, but when Castiel touches his cheek with two of his fingers, his skin is so soft. He's so fragile, even now, screaming at the top of his lungs. "Shh, Dean," Castiel soothes, whispering. "It's all gonna be alright." He brushes his fingers over Dean's head, playing lightly with the bit of hair he's got. He can't help but smile.

Mary stands by the window still, never having left the room although she let Castiel hold Dean. When Dean starts quieting down, she lets out a breath of relief. She smiles softly as she sits in the chair in the corner, watching them. "I wish I could stop him becoming a hunter," she says quietly.

Castiel nods sympathetically. "I understand," he says. "But if it helps, he is one of the finest men I have ever met. And a great hunter." He smiles affectionately at the little Dean in his arms.

"I don't remember him at all," she says. "The way he was when you were here last year. I don't even remember the way he looks. You left me as the only one aware of angels, and you wouldn't let me remember my baby boy."

"I'm sorry, Mary," Castiel says, looking up at her with a sad expression on his face. She has tears in her eyes as she looks at Dean in Castiel's arms.

"What's he like?" she whispers.

"He's the bravest man you can imagine," Castiel starts. "He takes such good care of Sam, too. He would rather die than let Sam suffer more than he really had to." Castiel looks down at the boy in his arms. His green eyes are already beautiful as he looks up into Castiel's blue eyes. Dean is smiling now. "He's loyal. Especially to Sam, but to me as well. He's saved my life more times than I would care to admit. And he's kind, wise, caring, and loving, although he doesn't always show it. He's beautiful." He looks up at Mary, then, looking into her eyes. She meets his gaze. "I know you don't want him to become a hunter, Mary. But you would be so proud of him."

A sob escapes her and she stands. As she is leaving the room, she stops in the doorway and turns toward Castiel without looking at him. She stares at the ground. "Just put him to bed, alright?" she says, and finally, she looks up to meet Castiel's eyes. "Please, watch over him."

"I will," Castiel says, nodding at her. "Always. I promise." Neither of them says anymore until she has left the room, and Castiel is alone with Dean. He walks over to Dean's crib, looking down at Dean. They're both smiling, Castiel with more affection than he thought he had for Dean Winchester. It's still not a surprise though. "Now, you need to sleep, Dean," Castiel says, quietly. "You need your sleep so you can become the great man you are."

He's quiet for a while. "You're strong, Dean," he says. "You're strong every time you face the world knowing what's out there. Every time you look into the eyes of your worst fears. But you keep fighting to protect everyone, to protect your family. Because there's nothing you wouldn't do for them." Dean is starting to feel heavier. Tired. "You're so like your mother."

He tugs Dean under the small blanket in the crib, stroking his head with one of his hands. Dean's hand wraps around Castiel's one finger, and Castiel stays still, looking at the little boy. He smiles softly, as Dean's breathing, that's barely loud enough to hear, slows, and he falls asleep. "I hope you'll let me be a part of that family."

Castiel's not aware of Mary standing just outside the door. He didn't consider the fact that, angel or not, she wasn't going to hand over her baby and just go to bed. He doesn't know she stands with tears rolling down her cheeks and a hand firmly planted over her mouth to stop herself from sobbing out loud. He doesn't know the gratitude she feels for him – not for stopping Dean's crying, or for telling him all those things, or for telling her about her baby boy. Just for loving her son so unconditionally, so selflessly. So beautifully.

When he's made sure Dean is sound asleep, he sits down in the chair in the corner. He keeps his gaze locked on the crib, but he's going to return to the present soon. To the adult Dean.

After he leaves, Mary sits in the chair he just left. She watches Dean, expecting him to have nightmares or wake up crying any second, but for hours, he's at peace. He sleeps calmly, and it's one of the only times Mary remembers him doing that. She falls asleep in the nursery, not waking up until the next morning when John shakes her awake.

Castiel's watching Dean in his motel bed. Barely a second has passed since he left. He glances to Sam now and then, only to check that everything's alright, and everything is.

For about an hour, Dean is having an uneasy sleep, and Castiel wants to wake him up, but he doesn't. He sits on the side of Dean's bed, watching Dean, not sure how long he can resist running a hand through his hair. Eventually, he does, and Dean tenses for a moment in his sleep, but then he relaxes. His dreams are calm again, and Castiel sits back in his chair, watching them.

He watches over them all night. He doesn't move for a second, his eyes always on one of them.

He watches over them. He made a promise.

AN:

Inspired by Caroline's (snowprincecas on tumblr) post. You can find it under her deancas or her destiel tag.

This was just a little thing I decided to do for some reason. I liked it. It's literally 6:55 in the morning and I literally just finished it though, so the quality might be questionable. I'll find out when I wake up later.

So yeah, hope you like it! Leave a review if you like!

Lea