A/N: Dean and Cas get an unexpected guest.

XXV. The Third Man

It's Christmas Eve.

Dean and Cas hosted dinner this year—Dean still hasn't figured out when Cas became such an awesome cook, but he certainly isn't complaining.

Tonight, Sam and Jess came over, along with Lisa and Matt. They'd invited Anna, but she'd already booked tickets to California weeks ago. They'd also asked Matt to bring Jody and Owen along, but Jody had laughed off the invitation, saying that this was a "young adults'" gathering and that she and her younger son had no place there. She had sent a few pies over though, so Cas hadn't had to worry about making a giant mess in the kitchen.

Now everyone's gone home—Sam's staying with Jess tonight. The dishes have been washed, the leftovers put away, and Dean's tugging Cas down the hall toward their bedroom.

"What's the rush? We have all night," Cas says as Dean pushes him against a wall. Dean steps in close, nips at his ear, and Cas lets out a contented sigh.

"God, Cas, want you," Dean murmurs, pressing his hips forward to grind their erections together.

Cas isn't fully hard yet, but Dean can tell he's getting there. Cas pulls Dean's head back, and their lips meet, and okay, foreplay is awesome, but Dean wants more—needs more.

Just when Dean's finally coaxing a reaction out of Cas—his hips are shifting, hands roaming restlessly over Dean's body—the doorbell rings. Dean's all for ignoring it, and when Cas tries to push Dean away, Dean just grabs onto Cas, pulling him away from the wall too.

Cas tears his mouth away. "Dean, we should answer that."

Dean only kneads his hands on Cas's ass instead, grinds their hips together nice and slow. "They're probably just some Christmas carolers," he mumbles into Cas's skin, and he pauses to leave a series of wet—very wet—open-mouthed kisses all the way up the column of Cas's neck to his jaw. "If no one opens the door, they'll move on."

The doorbell rings again.

"Well, that theory's shot," Cas says, wriggling out of Dean's arms. "Go get the door."

"Oh, you've gotta be kidding me," Dean groans, making a grab for Cas.

Cas dances out of Dean's reach. "It's my birthday, Dean. Be good."

"Do you not see this boner?"

Cas grins. "Answer the door, and I'll reward you."

With that, he disappears into the bedroom.

"Fuck," Dean hisses. Then he says, louder, "Fuck you, Cas!"

"Only if you behave!" Cas shouts back.

Dean groans again before going back down the hallway, willing his erection away because the last thing he wants to do is traumatize some poor kids who are out singing Christmas carols. The doorbell rings again as he reaches the first floor, and he calls, "Coming, all right? I'm coming!"

He pauses in front of the door, only half-hard in his sweats now, but he figures it's dark enough in the entrance that whoever's outside won't really be able to tell. After one last sigh, he pulls the door open.

Outside stands a single boy, not the carolers Dean had expected, and Dean frowns. "You uh, with the Boy Scouts or somethin'?" he asks.

"No," the boy answers, and okay, maybe not boy. He's more like a teen—fifteen or sixteen by the looks of it—and he's carrying a backpack and a duffle bag.

"Okay…" Dean says. "So what are you doing here, kid?"

The teen is silent for a moment, looking at Dean uncertainly. "You… you can't be… John Winchester."

Dean blinks. "Uh. No. You uh, you lookin' for him?"

"Yes."

"Why?"

The teen shakes his head. "Who are you?"

"Uh, you're the one standing on my doorstep. Who are you?"

"I just—please. I need to find John Winchester."

"Okay, fine. He's not here. Now who are you?"

"I'm his son."

Dean stares. Breathes. Blinks a few times, and keeps staring. "No, you're not. I'm his son—me and my brother. You can't—" but Dean cuts himself off at the look on the kid's face, because he doesn't understand that expression at all—something caught between angry and sad and wistful…

The teen laughs, but there's no humor in it. "Right. Right, yeah. Of course he'd have sons already. I…" he shakes his head again. "Any idea where I can find him?"

Dean snorts. "Yeah. Try Orlando." Dean goes to shut the door, but Cas's voice stops him—

"Who's there?"

Dean glances to the side and sees Cas standing down the hall from him, and he's changed into sweats and a t-shirt. Dean's willing to bet Cas isn't wearing anything under the sweats. His cock jumps at the thought, and fuck, fuck, fuck, he's gotta think about something else. There's a stranger here.

Cas steps to Dean's side and looks out at the teen. "Hello," he says.

"Cas, it's fine. Let's go," Dean says, because he doesn't want to deal with Dad's messes, not right now. Not on Christmas Eve, not when all he wants is to spend time with Cas.

"Yeah, whatever. I'll just… go," the teen says.

"No—wait," Cas says, stepping in front of Dean to keep him from closing the door. The teen looks like he's trying to hide it, but Dean can see how hopeful he is. "What's your name?" Cas asks.

"Adam. Adam Milligan. I uh, I took my mother's name. John Winchester is my father."

Dean clenches his jaw, shakes his head. "Look, there is no way Dad was unfaithful to Mom, okay?" Dean hisses into Cas's ear. "No way."

"How old are you, Adam?" Cas asks, and Dean grits his teeth.

"Sixteen."

"Dean, you're almost twenty-eight," Cas says. "Adam would have been conceived long after your mother's death. It wouldn't have been—"

"Shut up," Dean says.

Cas reaches for Dean's hand and squeezes it once. Dean tries to pull it away, but Cas's grip is as strong as usual. "Why are you here?" Cas asks the kid—Adam.

"My… my mom died. She got really sick, and… fuck. She didn't wanna ask for help, because she was too fucking proud, and I just…" he stops.

Dean can't help but feel sorry for the kid—he knows how it is to lose a mother—but he can't get over the fact that this might be his half-brother. No. It's not friggin' possible. Dad would never—because Mom, he loved Mom. Loves Mom. He couldn't…

"I don't wanna go into the foster system," Adam says, and his voice shakes a little, but everything comes tumbling out after that. "If I can't find a legal guardian, that's what's gonna happen to me, and I don't… I really don't want it. You guys… if you could help me find my dad, please—I'd only need him to sign some papers. I can take care of myself just fine. It'll only be for two years, and I'll be legal. I mean, my birthday's in September, so it won't even be two whole years."

"Cas, I don't think—"

"We can at least ask your father, don't you think?" Cas says.

Dean wrests his hand out of Cas's grip and walks away. "Yeah. Fine," he says, and he's probably angrier than he should be, but the last thing he wants is to find out that Dad slept with some other woman out there. And maybe that's stupid of him, to think Dad would have stopped having sex altogether, but… but Mom and Dad had that forever kind of love, didn't they? Mom's death broke Dad. How could he have a kid with another woman?

Distantly, Dean hears Cas letting Adam into the house, hears them talking in low voices as Dean skips up the steps and goes into his bedroom, because that's where he left his phone to charge.

He sits down on his bed and stares at the phone for a minute before calling.

"Dean?"

Dad sounds worried, and it makes sense—Dean doesn't call all that often, and right now they're in different time zones—it's maybe an hour later in Orlando. "Dad."

"What's wrong?" Dad asks. Dean hesitates—he doesn't even know where to start. "Dean?"

"You love Mom, right?"

There's a long silence. "Why would you ask that?"

"Why do you think?"

"Don't answer my question with a question."

"You answered my question with a question," Dean points out.

"Dean."

Dean figures he should just get it over with. "Do you have another kid?"

"What?"

"I'm not going to repeat myself," Dean says.

After another pause, Dad says, heavily, "How did you know?"

And it feels like a stone has dropped straight through the bottom of his stomach. Dean swallows. "So it's true."

"Yes. How did you know?"

"Adam showed up on our doorstep a few minutes ago," Dean says.

"What? Why would he—"

"His mom is dead." More silence. Dean really doesn't know what to make of it. "Aren't you gonna say something?" he prompts.

Finally, Dad says, "When did it happen?"

"I don't know," Dean says. "Do you wanna talk to him?"

"I… can't."

"You can't," Dean says, unable to hide the note of incredulity in his voice. He gets to his feet, because he can't sit through this conversation. "You can't even talk to him on the phone. So you're definitely not gonna come back for him then, are you?"

"Dean—"

"Dad, we just got a brother we never even knew about—your third son just showed up on our doorstep, and you're still not gonna come back here? Don't you even wanna know what the kid looks like?"

"Dean, I have a very important call waiting on the other line. I can't—"

"Yeah, all right, fine. Fuck you, too." He hangs up and turns his phone off, turns around in time to see Cas standing in the doorway, face carefully blank. "Oh, go ahead and take his side," Dean grumbles, tossing his phone onto the bed and folding his arms across his chest.

Cas shakes his head and says nothing as he crosses the room and pulls at Dean's arms. Dean lets him pry his arms apart, and then Cas is stepping forward, wrapping his arms around Dean.

"I'm sorry," Cas murmurs into the base of his neck.

Dean wants to be mad, wants to be indignant at Cas's pity, but he's just too tired.

When he finally opens his mouth to speak, Cas says, "No, don't," and Dean isn't even surprised that Cas knew he was about to talk. "Just listen, Dean. I'm sorry that your father doesn't have the strength to return and face you. I'm sorry that you can't have the close-knit family that you want."

Dean stiffens, and he wants Cas to stop talking, but he needs to hear what else Cas has to say. He starts to pull away, but Cas only allows him to back up about a step. He raises his eyes to Dean, and he looks steady and solid, looks like he could take Dean's weight if he collapsed right now.

"I would tell you to stop waiting, that it's much less painful that way," Cas continues, "but I know you won't stop, because that's the person you are. And I know that this doesn't change anything, but for what it's worth, I'm here. I'm waiting with you—Sam is waiting with you. You are not alone."

Suddenly all Dean wants to do is break down, but he forces himself to laugh instead. "Cas, keep it up, and we're both gonna grow vaginas."

Cas huffs a soft laugh. "Some things never change." Dean doesn't know how to answer that, so he says nothing. Then Cas says, "I set Adam up in a guest room down the hall."

Dean frowns. "Cas…"

"It's Christmas, Dean. He has nowhere to go. And if your father won't sign on to be his guardian… I really think you should."

"What? I can't—"

"He already said that he's mostly self-sufficient," Cas says. "And he explained his situation more clearly to me. They had to sell their house to pay for hospital bills. Adam stayed in a homeless shelter for a while and spent his days between school and his mother's hospital room. When she died, government officials came to Adam to get him set up in the foster system. They only let him leave because he said that he could go to his father."

Dean sighs. "Yeah. Yeah, all right, fine. I'll go talk to the guy."

Cas gives Dean a small smile. "I knew you'd make the right choice."

Dean rolls his eyes as he exits the room. "Mhmm, sure you did."

He heads down the hall to the only other room that has its light on. Cas's footsteps remain close behind him, and Dean can't help but feel grateful that Cas is here, because if he hadn't stopped Dean from closing that door, this kid would be stranded and homeless on Christmas. And… and even if Adam is proof that Dad slipped up, he's still… he's still family, which means that Dean will make sure he's taken care of.

Dean raps on the open door, and Adam looks up from his duffle bag.

"What uh, what did John—Dad—say?"

"I might've gotten into a fight with him. I'll give you his number tomorrow, and you can call him yourself, 'kay?"

"And… tonight?"

"Well, my uh, my better half says that you're stayin' here. So you're stayin' here," Dean answers. The kid's relief is palpable, and yeah, Cas was right—this was the right thing to do. "Did you have anything for dinner yet?"

"No," Adam admits. "I've been on a bus for twelve hours."

"We have plenty of leftovers," Cas says. "Come on downstairs. I'll get you something to eat."

"It's okay. I'm really not that hungry."

"Hey, you can't just skip out on food when you haven't eaten anything in so long," Dean says. "Come on." When Adam doesn't move immediately, Dean adds, "Cas isn't gonna let us go to sleep if you go to bed hungry, so you'd be doing me a favor."

"Okay, I'll eat," Adam says.

"Great," Cas says, and then he's walking away toward the stairs.

Dean lets Adam walk past him before following. "Have you ever met him? Dad, I mean."

Adam nods. "Once, a long time ago. I didn't really get to talk to him. My mom… they had a really big fight. I didn't know what it was about then, but thinking back, I… I'm pretty sure it was about me."

As they start going down the steps, Dean says, "Where are you from, anyway? What are your plans?"

"I'm from Minnesota. And I really don't have any plans. I just… all I want right now is to stay outta the system," Adam says. "I had a friend back at school who spent six years in the system before finding a foster home that really wanted to keep him, and I've heard tons of shit about it. I… I wanna go back to school, but right now, staying out of the foster system is top priority."

"Yeah, I hear you," Dean says, steering Adam toward the kitchen. He stops him just outside, and Adam looks up at him questioningly. "Look, kid. I—"

"Dude. Don't call me 'kid' unless you wanna be called 'old man,' okay?"

This surprises a laugh out of Dean. "Yeah, okay. Adam, what I wanted to say was… if things don't work out with Dad tomorrow, I uh…" Dean hesitates, but Adam's got this hopeful look in his eyes. "I'm your half-brother, and I'm…"

"Oh, for Christ's sake," Cas says, startling both Adam and Dean. They look over to see him standing in the entrance to the kitchen. "What Dean means to say is that he's willing to sign for you."

Adam looks at Dean. "You'd really do that?"

Dean had been reluctant when Cas first suggested it, and he hadn't even been really sure about it when he agreed, but looking at Adam—his half-brother—now, he has no idea why he even questioned it. "Yeah," he says. "Of course I would."

Adam breaks into a huge smile. "Thanks. I… really. Thank you."

Dean clears his throat. "Yeah, don't mention it."

When Adam opens his mouth to speak, Cas says, "He really means it when he asks you not to mention it. If you're gonna be staying here for an extended length of time, you'll learn that your half-brother is allergic to the larger spectrum of human emotion."

"Oh, shut the hell up, Cas," Dean says, and Adam laughs.

The microwave goes off then, and Cas goes back into the kitchen. Adam and Dean follow. Cas passes Adam a plate of roast beef, with mashed potatoes and squash on the side.

"Thanks," Adam says, taking the fork and knife that Dean hands over.

"You're welcome," Cas answers. "I'm willing to bet you're tired—Dean and I can leave you alone to eat. I'll get you a towel if you'd like to take a shower when you're finished. There's a bathroom next door to your room."

"That all sounds great. Thank you so much—both of you. I don't know what I'd…" Adam stops and looks down at the ground.

Cas places a hand on Adam's shoulder and gives it a squeeze. "It's really no problem."

"Don't stay up too late, kid," Dean says, and Adam shoots a glare in his direction, but there's no heat behind it.

Then Cas is herding Dean upstairs. Dean goes without protest until they reach the landing, where Cas shoves him in the direction of the bedroom and then goes off in search of towels for Adam.

Dean returns to his bedroom and thinks about whether or not he should call Sam. But after a moment of consideration, he decides against it—it'll be better to tell him tomorrow, because Sam's probably asleep by now, and if he's not, he's probably busy with Jess.

Arms wrap around him from behind, and Dean smiles.

"Merry Christmas," Cas says, and a quick glance at the alarm clock on the nightstand reveals that it is indeed after midnight.

"Merry Christmas," Dean repeats, turning around and pulling Cas close.

And it is a merry Christmas, because regardless of the circumstances, and regardless of what the outcome of Adam's talk with Dad will be, the Winchester family has grown by one, and Dean believes that that's a good thing.