A mysterious extraterrestrial girl named Lala runs away to Earth in order to avoid daily arranged marriage candidate interviews set up by her father, the king of her home planet Deviluke. Due to one of her own inventions, she teleports naked into fifteen-year-old Rito Y?ki's bathtub, and he accidentally feels up her breasts. It is later revealed to him that this is equivalent to a marriage proposal on Deviluke, and Lala happily accepts to become Rito's future bride. Rito, on the other hand, harbors feelings for a girl in his class named Haruna Sairenji and does not want anything to do with Lala.