What Was Missing

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Adventure Time - Season 3 - Episode 10

Adventure Time - What Was Missing

About this Adventure Time episode:
Adventure Time - What Was Missing is the 10th episode of Adventure Time season 3.
In this Adventure Time episode, Jake and BMO decide to give Finn some "alone time" with him and his piece of Bubblegum's hair, which he acquired in the second season episode "To Cut a Woman's Hair". However, a Door Lord suddenly materializes and snatches the lock, along with Jake's blanket, and BMO's controller. Finn and Jake chase through the creature's various doors, stumbling upon Princess Bubblegum and Marceline, who both appear to be victims of the Door Lord's theft. Finally, the Door Lord jumps through a door that the group is unable to get past. They realize that they must to sing a song to pass through the door; the group decides to create a band. Jake gets his viola, and Marceline retrieves her bass. Princess Bubblegum decides to play BMO as an 8-bit instrument, and Finn beat-boxes.
Tensions amongst the band members, however, boil over. Marceline sings a song ("I'm Just Your Problem") lamenting her and Bubblegum's estranged relationship, which almost opens the door, due to it being a song based on truth. Marceline and Bubblegum begin arguing, and Jake joins in; the band disbands. Finn, dismayed at his friends behavior sing "Best Friends in the World", bemoaning the fact that his friends are fighting. Bubblegum, Marceline, and Jake join in, and the four are able to open the door. Inside, Finn, Jake, and BMO reacquire their belongings. The group also finds a black rock t-shirt which they mistake to be Marceline's. However, it is revealed that it is Bubblegum's; it was a gift given to her by Marceline in the past. Marceline, embarrassed, chases Finn, Jake, and Bubblegum from the Door Lord's abode.