Ataru's mundane routine is forever altered when the alluring alien princess Lum, dressed in a tiger skin bikini, starts shadowing him at school. As if Lum's affections weren't enough, Ataru must also contend with the affluent and refined Mendo, who further complicates his life. Amidst the chaos, a parade of bizarre guests and educational tools disrupts his classes, featuring inept supernatural beings, a tapir with a taste for nightmares, and a camera capable of exploring parallel dimensions.