Finn and Jake are coaxed by a skeleton man to enroll in a course for free magic powers. After becoming full-fledged wizards, they realize they were tricked into helping stop an asteroid for all of eternity. Finn rejects the status quo and thinks of a different way to avert the crisis.

Finn and Jake, in hopes of helping a little girl named Penny get back her stolen basket, enter into a city where everyone is a thief, and become slowly corrupted by their surroundings.