The epilogue has some long dialog scenes. Sorry about that.
Kyle: Stan? Stan?
Stan: Sorry, what?
Kyle: Dude, you fell asleep again. You're lucky Mr. Garrison didn't notice.
Stan: Yeah... Thanks for waking me up.
Herbert: Boys! Pay attention!
Stan and Kyle smiled to each other after apologizing to Mr. Garrison. Cartman muttered "fags" under his breath, but they just ignored him. Ever since they replaced him with Kevin he had been unable to find another group who could stand him enough to hang out with him every day. Even Butters (who was his last resort) had told him to fuck off. Now he just sat in the background and made a few snide remarks every once in a while, which everyone ignored.
Kyle: So, are we still going to the arcade later?
Stan: Sure. Are you bringing your boyfriend along?
Kyle: Look, that's the sort of thing that made us drop Cartman. I told you not to make that type of comments.
Stan: ...Sorry. I didn't mean to insult you. I think it's great that you have someone, regardless of their gender.
Kyle: ...Thanks, I guess... Oh, and to answer your question: Yeah, Kenny is coming with us.
Herbert: Boys!
The boys apologized to Mr. Garrison again, and stopped talking for the remainder of the class. After class, they planned a time to go to the arcade and went home to drop off their things. Afterward, Stan hurried to the arcade. He wanted to be the first to get there and wait for his friends. Kevin arrived a few minutes afterward and both boys waited patiently for their other friends to arrive.
Kevin: So...
Stan: Yeah?
Kevin: What do you think my brother and Kyle are doing right now? You know they went to Kyle's together, right?
Stan: ...I'd prefer not to think about it.
Kevin: Oh, come on, you're not even a little curious? They've been dating for three years now, right?
Stan: That sounds about right... and no, not really. Not curious at all.
Kevin amused himself by annoying Stan for a few minutes until Kyle and Kenny arrived, holding hands, as usual.
Stan: You know, guys, everyone knows you're dating. You don't have to hold hands everywhere you go.
Kyle: Hey, we do it because we like it.
"If you say so..."
Kenny: Anyway, did you come here to analyze what we do or to play some games?
Stan: You've got a point. Let's go inside.
Kevin: Finally.
The boys went into the arcade, picked a multiplayer game and played it until they ran out of money. Afterward, they dropped off Stan, who was the one who lived closest to the arcade.
Kyle: We're still going back there tomorrow after school, right?
Stan: Of course. Kenny, Kevin, are you guys going too?
Kenny: If Kyle's going, I'm going too.
Kevin: Sure.
Stan: Alright then. Bye, guys.
The boys waved Stan goodbye, who went up into his room to do his homework. When he got there, however, someone was already waiting for him.
Kevin: Hey, Stan.
Stan: ...Weren't you just-
Kevin: Outside? No. This entire place is in your mind; you must know this.
Kevin was right. Six years ago, after Stan locked himself inside his own mind, he created a world where nothing bad ever happened to anyone who didn't deserve it, a world where everyone was happy and, most importantly, a world where he hadn't shot Kevin. Stan knew this world wasn't real, but the guilt he felt was too great for him to deal with. He chose to live in a world of his own making because of it.
From the stuff that Kenny told him (that he could understand, anyway), this world changed and mimicked reality as much as possible, whilst assuring that everything was still good for everyone who deserved it.
Stan: ...How do I know you're not in my mind too?
Kevin: I am, technically. But I'm as real as you are. In fact, we're the only two real things in this world... Well, Kenny and Kyle are now dating, but that's not why I'm here.
Stan: You haven't answered my question. How do I know you're real?
"Not this again. I come back from the dead (sort of) and you and Kenny can't even trust that I'm real?"
Kevin: ...I'm sorry, but I can't prove what I'm saying. You'll just have to trust me here.
Stan: ...What do you want, Kevin?
Kevin: You've served an important purpose, Stan. You don't even realize it, but thanks to you, Kenny and Kyle are now together, as they should be. Now it's time to make a choice, Stan. You can stay here if you want, but you'll never wake up. You will remain in this world for the rest of your life.
Stan: Or...?
Kevin: Or you can come with me.
Stan: ...Where would you take me?
Kevin: I think you know the answer to that.
Stan: ...Hell?
Kevin: What? Fuck no.
Stan: Why not? I shot you. I k... I killed you. If I could move, I'd kill myself right now.
Kevin: You don't deserve to suffer for what you did. I've forgiven you a long time ago. You should try doing the same.
Stan: ...How do I know you're not lying to me? How do I know that this isn't just my mind playing tricks on me?
Kevin: You don't. But if I'm real, you know damn well I would never send you to hell to be tortured for all eternity, no matter how many times you killed me. And if I'm not real, you have nothing to lose.
Kevin stretched out his arm in Stan's direction and opened his hand, with his palm facing the ceiling.
Kevin: If you take my hand, I will take you with me to heaven. But you can stay if you want to. I can't do anything to stop you.
Stan wasn't entirely convinced that Kevin was real, but he still considered his proposal as if he was. Kevin looked sincere to him, but he couldn't really consider anything in his own head to be real. After what seemed like an eternity, Stan chose. He took Kevin's hand and held it tight, just like Kenny did to him when he visited him in the hospital.
Stan: ...Let's go.
Well, that's the end of it. I hope you enjoyed it, despite what happened. To those of you who think the ending is lame: Sorry.
I will start rewriting my first four stories in a few minutes, but I have some stuff to do tomorrow and the day after, so it will take a while.