The Ice King loses his powers, reverts to his old human-self, and begins to wither away due to being over a thousand years old.
In the City of the Magicians, a magic spell backfires and turns back the Ice King into Simon Petrikov again. Now, with the help of Finn, Jake and Marceline, Simon discovers a way to bring back his beloved Betty. Finally reunited with the love of his life, everything is mathematical, but there's a problem, without his magic crown, Simon will die.—doko