[Classic Revival SOD AI Remastered] Ten years after her death in a traffic accident, his younger sister returns at the end of summer in the form of a lifelike doll. Her appearance must remain hidden from everyone, yet her words and movements feel as real as when she was alive. The soul residing within the doll's body is unmistakably his little sister. This story depicts the summer vacation they spend together—their first ever. Amid the fragile boundary between doll and soul, their bond grows ever deeper.