Finn, Jake and BMO arrive back in Ooo and discover that their home and the areas surrounding it have been entirely converted into candy. They also encounter Fern, N.E.P.T.R., Shelby, Lemongrab, Tree Trunks, Mr. Pig and Marceline who have been converted into happily brainwashed candy people. A frightened Sweet P is the only person who is still normal and directs the gang to a mysterious candy tower. The tower turns out to be Princess Bubblegum who has become a large candy being and attempts to convert the gang into candy people as well. While BMO is completely transformed, Finn and Jake are rescued by Ice King who takes them to the Sky Kingdom. As Finn and Jake look down, they discover that Ooo has been divided into four completely corrupted sections.
Adventure Time, originally titled Adventure Time with Finn and Jake, follows two best friends: Finn (a 12-year old boy) and Jake (a wise 28-year-old dog with magical powers), and the surreal adventures undertaken by the duo as they traverse the mystical Land of Ooo. A world built for adventure, Ooo is filled to the brim with various landscapes for the two buddies to explore and bizarre characters to assist.