|"The Vampire King"|
| Season 0, Episode 2|
|Airdate:||August 9, 2013|
| Written &|
| Bert Youn|
"Finn and Jake"
The episode begins with Cake telling Fionna a scary story about vampires as a bat flies past the Tree Fort on a stormy night. Fionna was really afraid, though she was unwilling to admit it. Fionna even asked Cake if the story was true or if she had just made it up. In response to Fionna, Cake said that a reliable source had told the story to her, making Fionna even more scared. And to finish the story, Cake said that the vampire used to haunt the tree where they live. Cake leaves her to sleep, but Fionna then sees a strange vampire-like figure in her window (proved to actually be Marshall Lee trying to find a way to get in the treehouse). Fionna goes downstairs out of fear and tells Cake. Cake then reveals that the story and "reliable source" were made up. Just then, the vampire, Marshall Lee, breaks in. After introducing himself, he tells them of hid adventures in the Land of Aaa. He then tells them that he owned the tree years ago, and proves it by showing them a large 'M' carved in the wall, but thanks them for keeping it warm for him. He then kicks Fionna and Cake out of their Tree Fort and they're forced to go house-hunting.
After a long montage (accompanied by the House Hunting Song), Fionna says she wants to go home, but Cake sings a song to her about how home is where your heart is. Fionna then realizes she would rather be with Cake, however Cake said that she rather be dancing with some hotties. Suddenly, Fionna and Cake settle in a cave they find, fix it up, and throw a party. Marshall Lee comes and interrupts the party and shows Fionna and Cake yet another 'M' carved into the wall, and that he previously owned it too, like the treehouse. Fionna is almost about to attack Marshall Lee, but Cake reminds her that home is where the heart is. Marshall Lee then prepares to take Cake (after Fionna says Marshall Lee can have the cave since Cake is her real home), but Fionna smacks her out of his hands.
Fionna and Marshall Lee start to fight. Marshall Lee grows into a giant bat. Fionna gets hurt, and Cake decides to attack him. He then bites Cake and sucks her blood, making him presumably dead. Fionna gets overcome with rage and fury and punches Marshall Lee in the face to make him stop, Marshall Lee then returns to his default form and kisses Fionna on the cheek after defeating him, making Fionna blush deeply, claiming that he enjoyed the fight. Cake comes back, showing that she survived by putting her guts in her thumb. Marshall Lee becomes amused and lets them have their old house back, as a 'gift' from him. When they get back, they find that their house is infested with worms. Queen Worm greets Fionna and Cake, then tells them to hug her. She then shoots a hypnotizing beam from her eyes, commanding the two adventurers to hug her. The episode ends with the GWQ (Giant Worm Queen) sending a signal, possibly calling more worms, as the brainwashed Fionna and Cake hug her.