(Past Rigby arrives home at night with his bike.)
Past Rigby: (laughing) Whoa! (he falls and goes inside) Yes! It's here! Aw, yeah, it's got my name on it and everything! You guys want to get the camera ready? Okay, okay, after, after, after. (He open the letter and reads it.) I didn't get in? But, everybody get in. What? What am I supposed to do now?
Sherm: Listen, Rigby, we were kind of expecting this, so we looked up an out of state school where--.
Past Rigby: Out of state?! But I'm supposed to go to college with Mordecai.
Barbara: Listen, this is only college that will accept you.
Past Rigby: Well, then, I won't go to college then! (Sobbing, he runs upstairs.)
Sherm: Rigby, you're going to college whether you like it or not!
Past Rigby: If I can't go to college with Mordecai, then I don't want to go to college at all!! (He slams his door, throws things off his desk, tears down his "College U" posters and turns on his console.)
Game: Welcome to College U, the College for accepts everyone.
Past Rigby: Meh!! (He flips his T.V. to the ground and falls to his knees, resembling Future Rigby's flashback. He looks at his letter, which has "Rejected" stamped on it in red.) How are Mordecai and me gonna stay friends if we go to different schools? (Gasps) What if he got rejected, too? (Things fade to white and shows Rigby's bike. Rigby is at Mordecai's house looking through his mail until he finds the letter. He opens it and reads before finding he was accepted. A typewriter falls to the ground as Rigby types rejected.) Sorry, Mordecai.
(Suddenly, Present Rigby tackles Past Rigby, grabs the forged letter, rips it and then tosses the typewriter into a nearby dumpster)
Past Rigby: Ow, what the heck man?(notices his future self) What did you do that for?
Rigby: Sorry, bro, can't let you do this. It isn't worth it.
Past Rigby: But if I don't, I'll lose Mordecai.
Rigby: But if you DO, you'll end up losing him anyway, that's one thing I can't let happen.
Past Rigby: But dude, we were supposed to go to college together.
Rigby: I know, but... Look, man, Mordecai is our friend, and even though sometimes we don't deserve him, he still has my back through all of this. You do this, he's eventually gonna find out, and trust me, in the future, we're gonna regret it a lot.
Past Rigby: What do you mean? What happens.
Rigby: Look, I'm not sure how me telling you any of this will effect the timeline, but I'm gonna tell you anyway. In the future, Mr. Ross tells Mordecai what we did, and we end up not being friends anymore. Not sure how, but somehow he ends up teaming up with Ross to stop us from altering the timeline, he ends up shooting and killing me, but our future self tells us to fix it before we die.
Past Rigby:(stunned at what he hears) Wow, that's crazy, bro. You're right.
Rigby: Remember this: A true friend wouldn't betray their friend like this. Do the right thing, tell Mordecai the truth.
Past Rigby: Ok bro.
(Rigby hands his past self his real letter and puts Mordecai's acceptance letter back into the envelope and into his mailbox, Rigby then fades away, as he stopped himself from lying to Mordecai. At the same time, the entire park gang of the future fades away as well)
Rigby: Good luck, me.(disappears)
(Suddenly, Past Mordecai starts walking toward his house)
Past Mordecai: Dude, did you see all that lightning? Must be a storm a 'brewing. (Rigby turns around, holding his rejection letter.) Hey, is that your acceptance letter?
Past Rigby: No, Mordecai, it isn't. I didn't get in bro.
Past Mordecai: What!!! Why?!?
Past Rigby: I don't know bro. Maybe I didn't study good enough, or I didn't try harder.
Past Mordecai: Wow bro, let me check and see if I got in. (Sees his letter and looks surprised) Dude, I got in bro. But... you didn't.
Past Rigby: What will that mean for us?
Past Mordecai: How about we try to finish that Time Machine and then convince you to study harder so we can get in.
Past Rigby: Um, I don't know, bro, maybe you should go without me, I wouldn't want you to miss out on a college experience if this goes wrong.
Past Mordecai: Dude, sure it would be a great experience, but without you there with me, I really wouldn't be able to enjoy it. Let's do this bro, and if it goes wrong, I'll say you were right.
Past Rigby: ok.
(They then go to their school's science lab, and sees a note)
Past Mordecai: dude, look
(Past Rigby grabs the note. The note reads: Dear past selves, sometime in the future, someone figures out a way to build time machines, and we decided to give you the instructions on exactly how to build the time machines in case something goes wrong. Sincerely, Mordecai and Rigby from the future)
Past Mordecai: Looks like our future selves went through this already and decided to warn us.
Past Rigby: Looks like it, bro. Now let's do this bro.
(The two high-five, and then get to work on finishing the Time Machine, following the instructions their future selves left them. Hours later, they finally finish the Time Machine.)
Mordecai: ok, let's do this bro.
Rigby:(takes a deep breath) hope this works. Go to, the first day of our senior year.(presses button)
(The duo are then sent exactly where they asked)
Mordecai: look, dude. There you are.
(Rigby then walks up to his past self then drags him behind the school)
Past Rigby: bro, why'd you drag me-(sees his slightly older self) wh-what's going on here, how did you get here?
Rigby: listen bro, I came from toward the end of senior year to warn you that you need to take your classes seriously. Listen we don't end up going to college with Mordecai, and we almost make a big mistake that could've costed us our friendship with him. So listen you need to study and keep your grades up if you want to get in to college, we can't not end up failing.
Past rigby: aw, what, studying suck-
(Rigby, taking a page from Mordecai, punches his past self in the arm)
Past Rigby: owww, fine, I'll do it, but not because you told me to.
Rigby: ok then. Good luck, bro.
(We then get a montage of Rigby paying attention in class, taking notes, studying with Mordecai, and even his parents and Don help him out whenever he needs it, and acing all of his tests and exams. Then the scene cuts to the day he received his college letter.)
Barbara: Rigby, your letter from College U came in today, sweetheart.
Sherm: We want you to know, no matter what that letter says, we're proud of you. You started taking school more seriously. And you and Mordecai were among the top students of your class. Z
(Rigby opens his letter. He then smiles.)
Rigby: I GOT IN. I GOT IN.
(His parents, and Don then hug Rigby)
Don: Congratulations, big bro. I knew you could do it.
Rigby: I gotta tell Mordecai about this.
(Rigby calls Mordecai)
Mordecai: Hello.
Rigby: Dude, I got in to College, U.
Mordecai: Really?
Rigby: YEAH!!!
Mordecai: ALL RIGHT, BRO. WE'RE GOING TO COLLEGE TOGETHER. I GOT IN, TOO.
Both: OOOOOOOOOOHHHHHH.
(Another montage shows the two graduating high school going on campus, taking their classes, and enjoying their college life. Soon their college years pass in a blur and they're both receiving their degrees, Mordecai in arts, Rigby in Game Designing.)
(The scene then cuts to the arriving at their jobs at The Park)
Rigby: dude, you ready to start this job, Bro.
Mordecai: Yeah.
Note: I know the ending is a little clichè, and I used Back to the Future as a reference, but I personally believe Rigby should've succeeded in stopping his past self from ruining Mordecai's life.
Next Chapter: TBD