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One thing Sam could count on was the fact that Dean always picked him up from Truman Middle School in the Impala. Sam would never admit it, but he loved the way that everyone's eyes watched him climb into the car. He liked how loud the engine was, and how the black paint reflected sunlight off into the eyes of the watchers.
“Hey, Sammy,” Dean would always say.
It was their little routine. It was a constant in Sam's life that he could count on.
Except for the day that it wasn’t.
…
Sam pretended to laugh at the joke Kevin told while his eyes searched the car circle. His day hadn’t been the best, and he was in no mood to listen to Kevin drone on about his grades. It was hot, he was sticky, and he wanted to go home.
Luckily, heaven came in the shape of a black Chevrolet Impala waiting next to the curb.
Sam quickly cut Kevin off from whatever he was babbling about. “Sorry, Kev, but I see Dean. He gets mad if I make him wait too long. See you tomorrow!”
Kevin nodded and waved him off, frowning slightly at the sudden interruption.
Sam made a dash for the Impala. He pulled open the passenger door quickly, the handle burning his palm. He wanted nothing more than to fall into the car and drive away from his bad day.
But there was someone in his seat.
“Sorry, Sammy,” Dean called from his place at the wheel. “Think you can ride in the back?”
Sam stared at the person in his seat. He had black hair that was sticking up like he'd held his head out the window on the drive over. He was wearing a white button down that looked four times too big and black slacks. If it weren't for his youthful features, Sam would've thought he was going to a board meeting. Especially because he had a tie dangling loosely from his neck.
Sam numbly closed the door and walked to the back seat, sinking down into it like his legs had given out.
Dean flashed him an apologetic smile from the rear-view mirror while he pulled the car into drive and pushed away from the school.
“Sammy, this is Cas. Castiel, this is Sammy.”
The guy-who-was-in-Sam's-seat turned around to look at him. He didn't smile, but his voice sounded utterly sincere when he said:
“It's very nice to meet you Sam.”
Sam merely nodded, his mouth hanging open from the corners. He looked at Dean, trying to silently communicate his “what the hell?!”
Dean didn’t take just anyone for rides around in the Impala. There’d been girlfriends, sure. A few good buddies, even, that had made the trek with Dean to pick Sam up from school. But they never rode shotgun. That was reserved for Sam.
Sam watched as Castiel reached down and fiddled with the radio. He expected hell to break loose. No one, not even Sam, could touch the radio.
“Driver pick the music, shot gun shuts his cake hole.”
But Dean did nothing.
Sam had, of course, heard all about Cas. He was Dean's friend. Probably his best friend. He never came over to their house, though. Sam had sat through a lot of car rides with Dean fuming about something Cas had done. (“The fucker called me out when I cheated on that stupid test!”) And even more about what he said (“Seriously, he called it a 'profound bond'. What the hell?”)
Sam assumed that Dean was pretty attached to the guy since it hadn't escalated into a fist fight. But he didn't assume that the guy got shotgun privileges. For the first time, Sam felt threatened. And by a guy in a wrinkled tie, nonetheless.
…
Castiel’s tagging along became a regular occurrence. It drove Sam crazy. Dean never explained why Cas got the shotgun. He never did anything except smile and throw out a greeting as Sam climbed into the backseat. Cas would sometimes ask how his day had gone, but Sam would never say anything more than “fine.”
Dean ignored all of Sam silent inquiries. Sam knew that Dean could sense them because his hands would always tighten on the steering wheel. When Sam asked outright why Cas was riding home with them, he would either get Dean's neutral response that they “were gonna hang out,” or Castiel's bland and lengthy explanations. There was never a discussion of shotgun.
The day that Sam opened the back door to find Cas passed out in the front seat, he thought he was going to lose it.
Cas was so comfortable in Sam’s seat. He was asleep, leaning against the window. He snored lightly, and for some reason that just pissed Sam off further.
“Dean,” Sam whispered after Dean pulled out into the road. “What the hell is going on with you two?”
Dean jerked so hard that the whole car swerved. Cas fell over onto the bench seat and woke with a start. He sat up, his hair standing on end, and stared around the car.
“Oh, hello Sam.”
Sam mumbled out what could barely qualify as a greeting, and then refocused his glare onto Dean.
Dean's knuckles were white against the steering wheel. “Nothing, Sam. Nothing! I swear!”
Cas looked between them, confused, before he settled against the window again. “Sam, would you like to accompany us to the movies?”
Sam agreed, and made sure to sit between the two of them when they got there. 'Nothing' his ass. Something was up, and Sam was going to find out what. He wasn't gonna let some asshole steal his big brother.
…
“So, Cas,” Sam started casually one rainy day. Dean was focused on the road, squinting through the downpour. “Don't you ever get tired of Dean? I mean you're always over.”
Cas blinked at him from the front seat. He was wearing that stupid tie again, and it was backwards. Why did Dean even hang out with a guy like this?
“I will never become tired of Dean.”
Next to Cas, Dean fell into a coughing fit. He pounded on his chest with one hand and gasped for air. “Jesus Christ, Cas!” He moaned. “You just can't say stuff like that!”
This time, Cas squinted at Dean. “Would you prefer that I lie?”
Dean shook his head, his eyes still wide. “Just, no. Shut up, Cas.”
Castiel turned back to Sam, throwing him a look of confusion. Sam threw one back at Castiel. Who said things like that?
…
Sam figured that Cas was the best person to ask about what was going on. He didn't exactly like the guy, but he had to give him points for bluntness. Dean would weave his way around any question, but Cas just dove right in.
The problem was, he never got to talk to him alone. Dean was always around. When they played basketball in the driveway. While Cas filled out his homework in their living room, because apparently it was normal to go to someone else's house just to sit quietly and do homework.
Even when Cas just seemed to be hanging around their house, Dean was in the room. Sometimes Sam wondered if they should just get Cas his own bed. He slept over enough times that it would make sense.
It was weeks before Dean actually left the two of them alone. They were watching Star Wars when Dean announced that they needed popcorn and got up to make some. Sam pounced the moment he was able.
“Hey, Cas,” he said quietly. “What are you and Dean? Like what's going on with you two?”
Cas tilted his head. He shifted on the couch, clearly uncomfortable with the question. “What do you mean?”
Sam pursed his lips. “It's just that you're always around. And you ride shotgun. Dean never lets anyone but me sit there. What's the deal?”
Castiel's eyes slid to the TV. He fidgeted again. “I'm not allowed to tell you.”
Sam's eyes widened. Questions flared through his mind faster than he could get them out. “What do you me-” he managed, before Dean burst back into the room.
“Soup's up!” He cried, flopping in between them. Sam saw Cas relax, but he felt himself tense.
There is only one reason Cas wouldn't be allowed to tell him the specifics of their relationship. Dean wouldn't have sat down and discussed with Cas about keeping their friendship a secret.
It dawned on Sam in a flash. It wasn't a friendship.
…
Suddenly the car rides home became a lot more awkward. Dean noticed, but he couldn't seem to figure out why. Cas didn't seem to be bugged by the silence.
Sam was the only one drowning in tension. He didn't have a problem with his brother having a boyfriend. I mean, sure, it was weird. He'd never said anything about that before.
Sam only had a problem because it was all a secret. Not only was Dean replacing him, but he didn't even trust him enough to tell him exactly who he was replacing him with. Sam felt like someone had flushed his heart down a toilet.
He spent his car rides moping in the backseat. His eyes would sometimes flash between the couple (because, shit, that's what they were) and he would feel his chest tighten. Whenever Cas invited Sam on one of their dates (holy shit he'd tagged along on their dates) he always declined.
Dean became increasingly distressed. His eyes were always on Sam in the rearview mirror. He'd hiss into Cas' ear with questions of “do you know what's up with him?”
Cas wouldn't know, of course. Because he didn't know he was replacing Sam. He didn't even know that Sam knew. Because of that, Sam just couldn't bring himself to hate the guy.
Finally, after weeks of silence, Dean couldn’t take it anymore. He pulled the car onto the side of the road and put her in park.
“Alright!” He yelled. “Someone is going to tell me what the hell is going on!”
He was met with two confused glances and long, dead silence.
“Don't pull that shit with me! Sam, you barely talk anymore! I feel like I haven't seen you in forever! You never hang out with us anymore.”
Sam pressed his lips into a thin, flat line. “Yeah, well,” he growled. “I figured I was doing you both a favor.”
Dean looked shocked. Cas looked confused.
“What the hell are you talking about?”
Sam crossed his arms and stared out the window. “I'm not a goddamn idiot, Dean! I know you two are dating!”
Dean reeled back, like maybe if he leaned far enough he could escape the words. Cas tilted his head.
“H-how did you...” Dean muttered.
Sam turned his glare onto his brother, and he got no satisfaction when he flinched. “It's obvious! Dean, if you're gonna replace me the least you could do is be outright about it! I don't give a crap if you're gay or whatever, but you've been lying to me about everything!”
Cas broke into the conversation. “You feel like I am replacing you?”
Sam nodded. He ignored the tears stinging in his eyes. He was in middle school. He wouldn't cry. He could take abandonment like a man.
Cas turned to Dean. “Am I replacing Sam?”
Dean's head flipped to Cas. “No, of course not. Sam's my brother. You're my...not my brother.”
Cas turned to Sam expectantly. “I'm sorry,” he said. “I didn't think that you felt that way. I promise not to come between you and your brother.”
Dean looked back at Sam, his eyes hesitant. “Yeah. Sam, I can't...I wouldn't replace you. You're my brother.”
Sam suddenly felt very small. “Okay,” he whispered.
Dean pulled back onto the road in silence. Sam felt that if he peeked over the edge of the car seat he would see Cas holding his hand.
“Do you really not care about...you know?”
Sam almost snorted. Instead, he just sighed. “No. I don't care at all.”