During spring break, just before her second year at Nagi High School, Usami Totoko's parents were transferred overseas, and she started living alone. She is trying her best to become an independent girl so that she can keep her beloved dog, but...she has no ability to live on her own at all, to the point where the store clerk disses her for buying three meals at a convenience store for a week in a row. One day, Usami happens to be saved from a fire by the store clerk, but the apartment where the store clerk lives unexpectedly burn down! The clerk, who had lost his house, decided to take care of Usami in exchange for living in her house! His name is... "Inu"-kun!