The story introduces characters in a fantasy land including Fin the human, Jake the magic shapeshifting dog, the Ice King, Bubblegum Princess, and villains like the Lich, Go To Sleep, and Slenderman. The Lich is freed from its cage and tries to destroy life, so Fin and Jake set out to kill it and its friends Go To Sleep and Slenderman. However, Bubblegum Princess dies in the battle and the villains manage to escape by entering snails, so they are not truly defeated.