Morimura Aiko is a junior high school student who is shorter than her peers. Ten years ago, her father went missing after going on a yacht trip. Her mother, a hat designer, left for Paris, leaving Aiko in the care of her uncle, Mr. Fujinami. Aiko had a pet dog named Papi, but he died in a car accident. Around the same time, another dog named Spank appears in her life. After experiencing so many unfortunate events, Spank's presence starts to bring joy to Aiko's life and puts a smile on her face.
