The thing is, Sam left hunting but he didn't forget everything he learned. He's only been at school for a year when this new guy shows up. Brady brings him to a study group, claiming he's a family friend but the way his eyes dart back and forth and his hands shake let Sam know that, whoever this guy is, he's not family and he's not a friend.
Still, he smiles up at the guy and says, “Hi, I'm Sam. Nice to meet you.”
The guy nods solemnly and says, “Nice to meet you, Samuel. My name is Castiel.”
The hairs on Sam's arms stand up. When Jess gives out her usual “Sam I Am” joke and Castiel's eyebrows wrinkle in confusion, he knows something is seriously wrong.
He doesn't want to upset his friends though, so he keeps his smile up and resolves to take care of it as quietly as possible.
He starts with Brady.
“So, family friend, huh?” He asks that night as they're heading back to their dorm. “Who's friend?”
“Uh,” Brady says, the color draining out of his face. “Uh, he's my mom's cousin's friend's son.”
“Oh,” Sam nods, as if he believes anything Brady is saying. “How'd you two meet?”
“Reunion,” Brady says shortly. Sam doesn't bother to ask if he means family or class reunion. He's hyperventilating enough as it is.
Instead, he goes to Castiel himself.
“Hey!” He says brightly when he catches sight of Castiel in the on-campus coffee shop. “What are you up to?”
“I have never had coffee,” Castiel says instead, staring blankly up at the menu. “Jessica says that is a sin. I do not believe so, but I admit I am not the most knowledgeable when it comes to such matters.”
Sam's smile falters a little but he orders two coffees, one with three shots of espresso like he's been drinking for years and one black.
“I don't think it's a sin,” he says as he hands Castiel the black coffee. “But even if it is, you can ask God for forgiveness and drink this as repentance.”
“Thank you, Samuel,” Castiel says, taking the cup. He looks down at it for a moment before looking up at Sam, a little suspicious. “What do you know of sinning?”
Sam thinks back on the dirty feeling that's been following him since childhood and says, “I know we all do it, no matter how hard we try. But I also know God will forgive us if we ask and work hard not to do it again. At least, I hope so.”
“You are very wise,” Castiel says before walking off.
Sam stares after him, only realizing after he's gone that he never got a chance to interrogate him. He decides to move to Plan B.
He writes down everything he learns about Castiel, either from other people or the man himself. He showed up suddenly because of something Brady won't or can't talk about. He refuses to use any sort of nickname with anybody, but he never calls Louis by Lauren either. He only eats and drinks the plainest, most unprocessed food, but he indulges when someone asks. He's very religious, constantly asking other people about their views on sinning and God and various other topics. Silent, inconspicuous, can apparently read minds, always carries some kind of dagger, constantly disappearing on Thursdays. Sam spends months taking notes. He writes every little thing down and carries it with him to the mythology and folklore section of Stanford’s library.
The next day he sits in a park under a tree and prays.
‘Castiel, Angel of Thursday, please hear me. I know what you are. I don't know why you're here, but I think it's because of me. If it's to save me, please tell me. If it's to kill me, please just get it over with.’
Before he can get much further, he hears a rustling sound and looks up. Castiel stands in front of him, a twisted look on his face.
“It's to kill me, isn't it?” Sam blurts out, fear soaking his palms. He doesn't move.
“Samuel,” Castiel says again, anguished, before sinking down to his knees. “Samuel Winchester, you are a good man. You are not free from sin, yet you do not revel in it. You have love in your heart and faith in your soul. You stay clear of temptation and hold firm against evil. Despite what has happened to you, what they fear you will become, you are a good man. I cannot kill you.”
Sam leans forward and grasps Castiel's hand in his. “If I'm going to do something bad, and you can stop it, please do whatever it takes.”
“No,” Castiel denies, looking at their hands in wonderment. “You sacrifice yourself and touch a warrior of God in friendship. You shall not die today.”
“You have to do something,” Sam reminds him, warm all over from the amazement Castiel is flooding him with. “It's your job. Your duty.”
“I will ask God for forgiveness.”
“If I ask and work hard to repent, He will forgive me,” Castiel tells him, heartbreak in his eyes. “You taught me that.”
“Goodbye, Sam. We'll see each other again.”
And Sam wakes up, curled in his bed and fuzzy from sleep. He shakes the dreams from his mind and wonders, just for a moment, who he's met with such sad eyes. He tries to keep them in mind all day, checking every person he knows, but with each different pair of eyes the dream fades away and he focuses on other things.
That night, he asks Jess if she'd like to get dinner sometimes, just the two of them.