(Episode starts in Eileen's house, where Mordecai, Rigby and Margaret are watching a TV show.)
Man on TV: And now, commentary from RGB2!
RGB2: If you ask this old-timer, TV peaked in the 80s! Why don't shows have laugh tracks anymore?
(Eileen pokes her head out from the kitchen.)
Eileen: Sorry to keep you guys waiting. I know you're hungry but my famous peanut butter and celery appetizers will be out in a jiffy.
(The TV switches to an advertisement for Seeds of Agony by Jonno.)
Jonno: Audacieusement modern, contrasté, avant- ... garde. These are all words you might say when you gaze upon my piece, Seeds of Agony. (Zooms out to show a giant strawberry behind her.) You won't want to miss this cultural event before it is taken by blimp back to my minimalist region studio and destroyed. The venue? (Laughs.) A transitional local between the realms of light and dreams.
(TV shows a map which displays where Seeds of Agony is.)
TV voiceover: Off of Spruce and I 95 at dusk by the Cheezer's. Saturday only!
Jonno voiceover: Whimsical!
(Shows the three on the couch.)
Mordecai: Wow, that sounds crazy.
Rigby: (Laughs mischievously.) Crazy enough to work!
Mordecai: Dude, what are you talking about?
(Rigby leans over to whisper to them.)
Rigby: Can you guys keep a secret? (Checks to see if anyone is watching.) I'm taking Eileen to see that tomorrow! And you guys are coming with! And, you're not gonna ruin the surprise!
Margaret: It sounds a little intense.
Mordecai: And why's it gotta be a surprise? Is it a special occasion or something?
Rigby: No, and that's the point! She'd be expecting something if it was. I've made her laugh, cry, scream with terror when she fell into that cave hole; all the big emotions. But she's too smart to be surprised!
Mordecai: No way.
Rigby: If there's a mystery, she has to solve it. Whenever I try to surprise Eileen, she figures it out immediately.
(Shows a flashback scene of Rigby dressed in murder-mystery-style clothing.)
Rigby: Good evening, my lady. I'm here to warn you that trouble's afoot. You see, there's been a mur-
Eileen: (Squeals) You're taking me to a murder mystery, right?
Rigby: Uh... yes.
Eileen: Great! I already picked out a dress so we could go!
(Shows another flashback scene. Rigby is holding a telescope and not wearing any special clothes.)
Rigby: Surprise! I'm taking you-
Eileen: To the conjunction of the Moon and Mars up on Lookout Mountain? I know! I'm so excited!
(Shows another scene where Rigby is simply at Eileen's house without any items or clothes.)
Eileen: You're taking me to the biannual mating season of the Hermit Crabs? You're the best!
(Cuts back to the house.)
Rigby: She's smart like that, dude. So I thought of a plan so crazy she'll never figure it out. Will you guys help drive us around?
Mordecai: Dude, you're being kinda crazy, but at least it's a nice kind of crazy.
Margaret: I think that's sweet Rigby. Of course we'll help you.
(Eileen walks into the room carrying a tray of celery and peanut butter.)
Eileen: Who wants celery and peanut butter? Wait, I smell a surprise brewing.
Rigby: No. You don't
Eileen: You're taking me to a movie after this.
(Rigby jumps off the couch.)
Rigby: Ha, noooo!
(Walks up with his face close to Eileen's head.)
Rigby: Is there even a surprise at all? Who's to say?
(He walks away. Eileen thinks. Margaret and Mordecai pretend to not know.)
(Transitions to the coffee shop. Eileen is working when Rigby walks in. He is wearing beach shorts, a formal jacket, and a hat. He is holding a flower.)
Eileen: I'm gonna say, based on your beach-casual look, combined with formal jacket and corsage, we're going to... Beach Prom! That's the most fun party of the year!
Rigby: Oh, Eileen, Eileen, Eileen, Eileen. I have a different surprise in store for you. And this time, you're never gonna be able to guess it! Now ditch the apron, we're heading out.
Eileen: Wait, but I still have to work.
Rigby: Talked to your boss, it's taken care of.
(They look over to where a random guy is.)
Random guy: Hey, fifty years from now, are you gonna remember bussing tables, or the greatest adventure of your life? Now get out of here you crazy kids.
Eileen: Rigby, I don't know who that is.
Rigby: He's a guy who gets it. But don't worry, I did talk to your boss.
(They walk out together.)
Eileen: Hmmm, if it's not Beach Prom, are we going to Costa Rica?
Rigby: No need to guess, just enjoy the surprise.
Eileen: Maybe your outfit is a red herring.
(They walk over to where Margaret and Mordecai are waiting for them next to Margaret's car. They pretend to be randomly running into them.)
Margaret: Woah... Craaaazy running into you guys. Soooo random.
Mordecai: Need a lift?
Eileen: (Thinking) But that could also be a red herring of said red herring, meaning... (Puts on a jacket from inside the car.) Beach Prom!
Rigby: JUST GET IN THE CAR!
(Transition to the four driving.)
Eileen: I'd say we're about fifteen miles outside of downtown heading northwest. The temperature has dropped approximately three degrees, which puts us near that shoe store I like, but... (Calculates on her fingers.) Yup, we'd overshoot it by about nine-hundred feet. (Notices Sea Turtle Fan Club at the Super Hotel 25.) Ah! Sea Turtle Fan Club! I just paid my dues! That's so nice, Rigby!
(Rigby's watch beeps.)
Rigby: And... time to turn around. (He puts on a doctor's shirt and hat, as well as a stethoscope.)
Rigby: Uh, make a u-turn up here!
(They turn around and eventually get to the Park.)
Rigby: Alright, everyone get out and go behind the house.
(They walk behind the house, where there is rope, three chairs, a cardboard box, tiki torches and a parachute. Eileen thinks. The scene shows a first-person view of Eileen's brain, which looks like a futuristic computer. She combines the items to show a hot air balloon.)
Eileen: I've got it! You're building a hot air balloon with all this stuff for us to ride in!