After another failed attempt to catch Dennis when he is causing trouble, Sergeant Slipper's job is on the line. Slipper's boss hires a super-efficient cop called Boot to replace him, which apprehends most of the residents of Beanotown for the most insignificant of actions and sets out to ban all modes of fun for everyone else. Teamed with Walter, Dennis plans to ensure that Slipper keeps his job and Beanotown returns to normal.