Subaru Mikazuki, a 23-year-old mystery novelist and awkwardly bashful person, is a huge introvert. He'd rather stay at home and read a book than go out and connect with others. His parents sadly perished in an accident many years ago, leaving him alone in the world, worsening his life of loneliness. Subaru comes up a little grey and white cat named Haru while making sacrifices at his parents' grave one day, which he ends up taking home with him. Subaru, on the other hand, has never cared for anybody else in his life—can he even care for a cat? Haru is thankful to Subaru since he provides her with unlimited food—a luxury for a cat who is used to a harsh environment.