As a junior high school student, Morimura Aiko is noticeably short for her age. Her father's disappearance during a yacht excursion a decade ago remains shrouded in mystery, while her mother, a renowned hat designer, relocated to Paris, leaving Aiko under the watchful eyes of her uncle, Mr. Fujinami. Tragically, her beloved pet dog, Papi, passed away in a car accident around the same time. However, a ray of hope enters Aiko's life with the arrival of Spank, another canine companion. Despite her tumultuous past, Spank's companionship brings joy and happiness back into Aiko's life, illuminating her world with newfound hope and optimism.