Jack must chase a mysterious thief who stole his clothing while he was bathing, but things get complicated when his pursuit leads him into another world, whose denizens could gaze on his nudity.
While investigating the destruction of several scattered villages, Jack learns that Aku’s new “ultra-bots” are responsible. Unable to destroy them, he receives assistance from an unexpected source: their creator.
Aku leads Jack into a cursed graveyard, where he is attacked by an army of undead warriors. Jack defeats them, but then discovers Aku’s true plan: kill Jack with his own sword.
Centuries ago, the demon Aku is accidentally released by Jack’s father, who receives a magic sword from the gods. Eventually, he uses the same sword to imprison Aku beneath the earth.
Seeking to end their struggle, Aku proposes a one-on-one duel between him and Jack, with neither combatant using their magic abilities. Jack agrees, but Aku’s honesty is unclear.
Jack is transformed into a chicken after bumping into a cranky wizard and winds up being captured by a greedy man (Luther Creek) who seeks to turn him into a prizefighter.
Jack finds a booby-trapped labyrinth, in the center of which is a diamond which could send him back to his own time. But a mysterious stranger, who has also entered the maze, could put Jack’s plans in jeopardy.