What Was Missing

Synopsis
Finn and his friends must come together and play music as a genuine band in order to open the gate of the Door Lord and retrieve their stolen items.

Plot
The scene opens to Finn checking to see if no one else is home before pulling the lock of Princess Bubblegum's hair from the episode,"To Cut A Woman's Hair" out from under the couch. He sits down and cuddles with it until Jake comes out from behind the couch with BMO. Jake tells a startled Finn that he already knows about his "private time he spends with the wad of Princess Bubblegum's hair." Jake then picks up a floor board and pulls out his baby blanket to show Finn a special object of his own. Then a door appears and out hops a Door Lord. He snatches Finn's wad of Princess Bubblegum's hair, BMO's controller, and Jake's blanket. The three follow the Door Lord through a door that leads to Princess Bubblegum's castle, where she is seen running after him and demanding that he come back, yelling "Get back here you thieving door lord! You butt!" which helps identify the creature to Finn and Jake. The Door Lord then opens another portal, which Finn, Princess Bubblegum, BMO, and Jake follow through into Marceline's house. Marceline is trying to hit the Door Lord with her bass, until he opens up a final door that hurts Marceline with the sunlight through it. The group, now with Marceline, who has put on a pair of gloves and a sun hat which will protect her from the sun, and Princess Bubblegum, go through the final door into "Red Rock Pass," chasing the Door Lord until he escapes into a double door that closes in front of the four. Finn then reads the words that appear on the archway that say: "This door shall yield to no command save for a song from a genuine bande."

The crew then tries making some music to tempt the doors to open using their assorted instruments, but when Marceline begins to sing about wanting to "drink the red from your (Princess Bubblegum's) pretty pink face" Princess Bubblegum comments that her lyrics are "too distasteful." Marceline then replies defensively, "Oh, you don't like that? Or do you just not like me?" Bitterly, Marceline sings I'm Just Your Problem to Princess Bubblegum, inducing shocked reactions of silence from the princess, Jake, and Finn. Since the door reacts to the truth (later realized by Finn) and the door reacted to her song, the lyrics to Marceline's rock ballad consisted of her true feelings. At the end of her song she stumbles, stammering something that isn't truthful ("to...to bury you in the ground... and drink the blood from your... urgh!") causing the faces on the door to stop responding to the music, and to dim. Marceline then yells "Stop staring at me!" Which may be a hint of her embarrassment.

Jake calls Princess Bubblegum and the others "talentless hacks" and leaves, only to come back again later (this is all part of his act as the band's self-proclaimed jerk). Finn suggests that they have a noodle break, taking a pack of dry, uncooked noodles out of his backpack. Marceline then starts to float off to the open door that the Door Lord left open, and Finn says in a panic: "No! Wait--don't go too!" Thinking that Marcy has decided to leave the band as well, but Marceline just tells him she's getting something to cook the noodles.

Finn continues to eat the noodles raw. Marceline comes back, with a pot and a mobile stove, and tells BMO "come here baby," and hooks BMO up to heat the pot of water, and Finn drops his noodles into the pot. The sun goes down, and Marceline takes off her hat. When Finn suggests a song about noodles, both girls say "No!" In unison, to which they all laugh shortly afterward.

Princess Bubblegum then tries to make a new song, and Jake comes back. Jake says: "Shut yo face, I came back for the music." After Princess Bubblegum's plan fails due to her "miscalculations," Marceline says that Princess Bubblegum wasn't as perfect as she had thought, and that she couldn't judge her anymore.

The two have a fight. Marceline then spits on Princess Bubblegum's jacket, and they all begin to leave, except for Finn, who then begins to sing a song of what his best friends think of him. Marceline, Princess Bubblegum, and Jake join in as Finn sings about how they were all "best friends in the world." The door, in response, opens to the Door Lord eating a sandwich in an empty room. The crew listens to his mumbling, and while Finn appears to be perplexed at them, Princess Bubblegum, Marceline, and Jake state that what the Door Lord had hoped for them to learn, that the real treasure was their friendships. The Door Lord smiles with glee at their revelation, but then he is shortly beaten up afterward by the five, presumably in retaliation to his thievery. Jake then passes out their stolen items. Finn receives his wad of Princess Bubblegum's hair, where Princess Bubblegum replies, "Oh, you." and Finn mutters under his breath "Yeesh." Jake gets his baby blanket and BMO gets its controller back. A black T-shirt with what seems to be cinnamon rolls strangling a snake is mistaken to be Marceline's, but is claimed by Princess Bubblegum; claiming she wears it all the time as pajamas causing Marceline to blush. At the end, it is revealed that the Door Lord hadn't taken anything from Marceline. The episode ends with Marceline in a monster form chasing after Finn, Jake, and Princess Bubblegum exclaiming, "I'll kill you!"

But Finn, Jake and Princess Bubblegum run out laughing as Marceline chases them.

Major characters

 * Finn
 * Jake
 * Princess Bubblegum
 * Marceline
 * BMO
 * Door Lord (antagonist)

Minor characters

 * Shelby (cameo)
 * Snail
 * Jam Jam
 * Cloud Person

Songs

 * "I'm Just Your Problem"
 * "A Song About Noodles"
 * "Bubblegum's Blueprint track"
 * "My Best Friends in the World"

"Mathematical!" controversy

 * For information on the controversy surrounding the "Mathematical!" video related to this episode, see: Mathematical!

Trivia

 * The oven, range hood, and cabinets in Marceline's house are now white instead of red, as they appeared in previous episodes.
 * In the scene where Jake claims that they've "all forgotten about the music," Shelby is seen outside of Jake's viola and quickly crawls back in.
 * While Princess Bubblegum, Finn, and Jake are chasing the Door Lord in Marceline's house, the title card music for "Hitman" plays.
 * When Marceline plugs the hotplate into BMO, the plug is two-pronged yet she puts it in what appears to be a single, round hole.
 * When the Door Lord steals a candy kid's toy, Finn jumbles the words up, shouting, "I'll get your kid back, toy," instead of, "I'll get your toy back, kid."
 * The Door Lord was trying to steal Marceline's bass but she fought back, which is the reason why she did not have anything in the Door Lord's bag.
 * The mathemathical formula Princess Bubblegum draws in the sand is called Euler's identity.
 * Princess Bubblegum uses the British English term for musical beats ("quavers") as opposed to the American English term ("eighth notes"), hence Marceline's confusion.
 * They were eating instant ramen noodles. The dry, uncooked noodles.
 * In the early story board, Finn was using a microphone while beatboxing.
 * Jake's viola says "toots" on the back of it as seen in "Gut Grinder".

Cultural References

 * When Princess Bubblegum plays 8-bit music on BMO, it is playing music from the original Megaman games.

Episode connections

 * The Door Lord looks similar to Key-per from the episode "The Enchiridion!." Key-per wore a key strapped to his head while the Door Lord wore a door.
 * In "Bad Little Boy," Marshall Lee and Prince Gumball are shown to have the same type of relationship as Marceline and Princess Bubblegum.

Errors

 * At the end when Princess Bubblegum is seen running away, her shirt is magenta instead of black and her dress was purple instead of pink.
 * The instant noodle set and the instant noodle suddenly disappear.
 * Near the end of "My Best Friends in the World" when Marceline is floating past Jake, the top of her bass and part of her hand disappear behind the background.
 * At the end when Marceline grows to chase everyone, her clothes grow as well.
 * When Princess Bubblegum was walking away, she wasn't carrying Beemo, but when Finn says "lost the piece of your hair" she is seen holding Beemo, the same thing happened when Finn said "the truth" and she turned around she wasn't holding Beemo, but when Finn continues to sing, she is holding Beemo again.
 * When Princess Bubblegum is seen running from Marceline, her ponytail is pink instead of purple.

Production notes

 * This episode was formerly titled "Door Jam." It was a pun on the musical term "jam" and on "door jamb," the name for the vertical part of a door's frame. However, the title was changed because the Adventure Time writers prefer not to use puns in episode titles.
 * The title card was designed by Michelle Xin and painted by Martin Ansolabehere.
 * In the storyboards Jake got his pants by asking (and yelling) at Marceline to let him borrow her pants from her home, and Marceline says she misses it when Jake was afraid of her.