(The episode starts out in the Tree Fort, Finn is squatting by a couch, looking around himself)
Finn: Fionna? BMO?
(He lifts a couch cushion and reveals a wad of gum stuck to the bottom of it; he pulls it off, sits on the couch, and prays for Lemongrab's convenient death; Fionna and BMO sneak out from behind the couch)
Fionna: Hey, bro, what you doing?
Finn: (Startled) Sis!
Fionna: Don't worry, bro. We won't tell anyone about the private time you spend with your wad of Princess Bubblegum's hair.
Finn:(Blushing) You guys knew?
Fionna: Finn, we're twins. And I know you always hold it when praying for Lemongrab's death.
Finn: I JUST CAN'T GET OVER THE WHOLE THING, FIONNA!
(Finn starts bawling; Fionna hugs him)
Fionna: I know it's hard, Finn, but you'll get through it. Here, I'll give you...
(She goes and lifts up a floorboard and pulls out a blanket)
Fionna: My old baby blanket.
(Suddenly a door unfolds in the side of the room and a Door Lord pops outs)
Door Lord: Hmmm! Hmmhmmhmmhmm!
Finn: Who the hell are you?
Door Lord: Hmm hmm hmm hmm!
(The Door Lord knocks over Fionna and takes her baby blanket; Finn puts up his fists)
Finn: Put 'em up, tough guy!
Door Lord: Hmmhmmhmm.
(Door Lord takes Finn's wad of Princess Bubblegum's hair and BMO's controller)
(Door Lord throws a key and another door unfolds, which he jumps through)
Door Lord: Hmmhmm!
Finn: Come on!
(They jump through the door)
(Jam Jam is playing with a toy train when the Door Lord pops in and steals it, with Finn and company in hot pursuit)
Finn: I'll get your toy back, kid!
Jam Jam: Boo.
Door Lord: Hmmhmmph!
(Door Lord throws a key high in the air; it unfolds a door in midair and he jumps through it)
Fionna: That guy must do crazy squats.
(Finn and company enter through the door, and Princess Bubblegum is chasing the Door Lord through her castle when he opens another door and escapes; Finn hides his face)
Princess Bubblegum: Come back here, you thieving Door Lord! You butt!
Fionna: Come on, Bubblegum!
Princess Bubblegum: Fionna? Where's Finn?
Fionna: Right there. He still can't get over the whole Lemongrab thing.
Princess Bubblegum: I don't blame him. I'm still getting over it, too. And I've been praying for his death these past few days.
Fionna: So has Finn. C'mon Finn!
(They enter Marceline's kitchen where sound of a conflict from her living room is heard; Marceline is fighting the Door Lord with her Ax Bass when he open another door and sunshine comes through it)
Marceline: (Hisses and fall on the ground)
(Door Lord jumps through the door)
Finn: Marceline! Are you okay?!
Finn: Don't worry. We'll get him.
(They go through the door and end up in Red Rock Pass; they chase the Door Lord until he pulls out another key and opens a giant gateway that closes before the group can enter it)
Finn: No! (Sighs) What? (Letter start to light up around the gate's frame) "This door shall yield to no command save for a song from a genuine band." What is this gripagrap?!
Princess Bubblegum: It's the door of the Door Lord, Finn. We used to lock them up, but they kept breaking out, 'cause they're Door Lords.
Marceline: (Wearing a sunhat and gloves) They broke out because you let them live.
Princess Bubblegum: (Angered grunt)
Finn: Hmm? The door said it will open for genuine band. Let's try and music this door open as a quintet.
Jake: Can I be the jerk it the band? 'Cause that's an important part of a band's success. Hmph.
Fionna: Where did you come from?
Marceline: I know how to get through this door. We're gonna lay down a chill jam.
Finn: Hey. Yeah, yeah, yeah!
Marceline: Just keep it cool. Got that princess?
Princess Bubblegum: Hmph. (Grabs BMO)
BMO: Ohh! (Princess Bubblegum pull off his face) Oh, my face!
(Princess Bubblegum starts to play with BMO like an instrument, BMO laughs)
Jake: Let's see if you hacks can keep up with my raw talent!
(Jake begins to play his viola, Finn begins to beatbox, and Fionna begins tapping on random rocks like drums)
(The song I'm Just Your Problem begins)
(The door glows brightly as it comes close to opening)
Finn: It's working! Look at the door!
(The song ends as Marceline loses her focus)
Marceline: ...To bury you in the ground... and drink the blood from your... Ugh.
(Door stops glowing)
Marceline: Stop staring at me! Ugh, you threw me off!
Finn: Come on, everybody! Don't stop now. The door was responding to our music! I wonder what it liked or what was missing.
Jake: Well, I know what's missing. Talent. I'm getting out of here, you hacks! Talentless hacks! (Leaves)
Finn: (Takes off his backpack) Maybe to be a genuine band we need to be nicer to each other and hang out as buds. (Pulls out a noodle cake) Let's take a noodle break. Come on, it will help!
(Marceline flies off)
Finn: No! Wait, don't go, too!
Marceline: I'm just gonna get stuff to cook that.
(Finn has already taken a bite of the noodle cake and puts his backpack back on)
(Marceline flies back into the door from her house)
Princess Bubblegum: That was sweet what you said about being buds.
Finn: Mm-hmm. Thanks. I just wish it was more than that between you and me, but that butt Lemongrab would interfere and ruin everything again! Why don't you just kill him?
Princess Bubblegum: If I were to kill him, every kingdom in Ooo would declare war on the Candy Kingdom and see to it that we are wiped off the face of the Earth.
Finn: Oh. (Groans)
Fionna: It's alright Finn. She didn't mean it, nor did she do it to torture you.
Princess Bubblegum: She's right Finn. I would never do anything to harm you, physically or psychologically. I'm so, so sorry.
Marceline: (Returning with a hot plate) I'm back yo! Come here, baby. (BMO comes and Marceline sticks hot plate plug into BMO)
(The sun goes down, Marceline takes off her sunhat and gloves, Finn sings A Song About Noodles and they laugh)
Princess Bubblegum: For our next attempt, I wanna be the lead.
Finn: Yeah! Sounds cool, my bud.
(Jake comes back dressed like a punk rocker)
Finn: Jake, you're back!
Jake: Shut your face. I came back for the music.
Princess Bubblegum: BMO, execute Sound Structure Alpha. (BMO begins to play a song) Marceline, begin playing triplet quavers in mixolydian mode.
Marceline: Alright, fine. (Begins to play her Ax Bass) Wait, what's a quaver?
Princess Bubblegum: Now, Finn, vibrate your uvula by dampening and undampening your larynx.
Princes Bubblegum: (Rubbing her neck, vibrating her voice) Go like this, silly.
Finn: Oh. (Does it) Whaaaa...
Princess Bubblegum: Fionna, just tap on random rocks like before.
Fionna: That sounds easy.
Princess Bubblegum: Okay, okay. Jake, are you gonna join in?
(Jake smashes his viola, Marceline looks agitated)
Shelby: JAKE! What the heck?!
Princess Bubblegum: Everyone, just stick to my blueprints. (Gasps) (BMO catches fire)
Finn: (Sighs) One more time?
Princess Bubblegum: I may have, um... miscalculated.
Fionna: Spoken like Mr. Spock himself.
Marceline: Ha! Looks like you aren't as perfect as you thought. Guess you can't judge me anymore.
Princess Bubblegum: I never said you had to be perfect!
Fionna: What are you guys talking about?
Marceline: Our past, which is none of your business!
Princess Bubblegum: Fionna has the right to know!
Marceline: She can never know! Neither can Finn or BMO or Jake, or, or, or the viewing audience!
Finn: The what?!
Marceline: And that's also none of your business!
Finn: Alright, time out, guys.
(Marceline spits on Princess Bubblegum causing her to recoil in shock and leave, with BMO following)
Finn: Princess! Princess, wait!
Princess Bubblegum: I won't stand to be insulted by my, my, my ex-lesbian lover!
(Finn, Fionna, Jake, and the "viewing audience" all gasp)
Finn: You?!?!?! YOU DATED MARCELINE!?!
Fionna: Best not let word of this reach those homophobic lynchers near Gumbal Junction.
Finn: Gumball Junction? Never been there.
Marceline: (Hisses) I TOLD YOU NO ONE CAN KNOW! EVER! EVER!!!!! Whatever, (Eyes start to water) Uoh! I'm outta here, too! (Leaves)
Jake: (Cries) You've all forgotten 'bout the music! I quit the band! (Runs away backwards) I'm just pretending!
Finn: Jake! Everybody! No...
Fionna: It's alright, Finn. No matter what they do, I'll always be with you.
Finn: You're right. We can beat the Door Lord! ...Together.
(Finn sings My Best Friends in the World, reunites the band, and opens the door of the Door Lord. Inside the Door Lord is eating a sandwich)
Door Lord: (Spits out sandwich) Hmm? Hmmhmmhmm.
Finn: It's over, Door Lord.
Fionna: So hand over our stuff, OR WE'LL KILL YOU!
Door Lord: Hmmhmmhmmhmm. Hmmhmmhmm hmmhmmhmmhmm hmmhmm hmmhmmhmmhmm. Hmm?
Finn: What's he trying to say?
Marceline: I totally get it. He may have stolen our treasures...
Princess Bubblegum: ...But by doing so, he showed us...
Jake: ...That the real treasure was friendship.
Door Lord: (Happy) Mmmhmmhmm! Mmmhmm hmmhmmhmm.
(The scene changes, the Door Lord has been killed and dumped in a garbage chute)
Jake: Okay, here's that lock of Bubblegum's hair you love so much.
Princess Bubblegum: Oh, from that abbreviated spaghetti dinner?
Finn: (Sighs) Ah, yeesh.
Jake: And here's Fionna's blankey. (Puts it on her face) Here's your controller, BMO.
BMO: (Happily twirls it) Yippie ki-yi-yay!
Jake: Marceline, here's your rock shirt.
Marceline: Hey, that not...
Princess Bubblegum: (Rushes towards it) It's mine! That's mine.
Marceline: You... kept the shirt I gave you?
Princess Bubblegum: Yeah. It, uh, means a lot to me.
Marceline: But you never wore it.
Princess Bubblegum: (Puts it on) Dude, I wear it all the time. As pajamas.
Finn: Wait, if that's Bubblegum's shirt, what are you missing, Marceline?
(Marceline is dead silent)
Finn: Wait a second, wait a second! You don't have a thing! You just wanted to hang out with us!
Marceline: No, I didn't!
Fionna: No way, you're caught! I figured you out! (Laughs)
(Marceline turns into a monster)
Marceline: I'll kill you knowing my secret!
(The episode ends with Finn, Fionna, Jake, BMO, and Princess Bubblegum running away from a pursuing Marceline laughing)