The Joker has returned and is committing robberies in which he tells a bad joke that surprisingly makes everyone burst out in a fit of laughter, then he robs everyone using a gimmick based on the joke which he tells. When Batman and Robin attempt to stop him they too find themselves caught in a fit of uncontrollable laughter. Caving a key out of the leg of a footstool in the cell using his photographic memory, Batman gets them out of the cell and they confront the Joker, beating him this time and lock him up, and leaving him to endure the mocking laughter of his fellow inmates.