A kitten wanders away from her mother during a walk and ends up lost near an apartment complex, where a young boy named Yohei and his mother Miwa find her and bring her home. Pets aren't allowed in the building, so the Yamadas have to hide her, and when she answers to the sound "chi" during her first attempts at housebreaking, the name sticks. Told largely from the kitten's point of view, the manga follows Chi's earliest days learning her new family's routines, the other animals around the neighborhood, and the rules of a home she isn't supposed to be in.