Finn, Lumpy Space Princess, and Gunter arrive in a radically altered Fire Kingdom. The inhabitants, which include Wyatt (voiced by Andrew Daly) and Lady Rainicorn, attack the heroes. Finn and Gunter try desperately to restrain their violent tendencies as it would allow the kingdom to corrupt them. Eventually the group find Flame Princess who has transformed into a dragon. When she swallows the jewel necessary to save Ooo, Finn gives into his violence and begins attacking Flame Princess. Lumpy Space Princess angered by the violence yells at everyone to stop their fighting. The kingdom misinterprets her anger and decide to start a war with the Candy Kingdom. Cinnamon Bun, who was unaffected by the corruption, frets that this is the end of Ooo.
Elenco: Jeremy Shada , John DiMaggio , Tom Kenny , Olivia Olson , Dee Bradley Baker , Hynden Walch , Pendleton Ward , Niki Yang , Steve Little , Polly Lou Livingston , Jessica DiCicco , Niki Yang , Maria Bamford .