Morimura Aiko is a junior high school student who is short for her age. Her father went on a yacht ten years ago and his whereabouts remained in obscurity. Her mother, a designer for hats, left for Paris, leaving Aiko in the care of her uncle, Mr Fujinami. Aiko had a pet dog, Papi, but it died in a car accident. Around the same time, another dog, Spank, appears before her. Having gone through so many unfortunate events in her life, Spank's presence begins to brighten up Aiko's life and put a smile on her face. (Source: Anime News Network)

Jun is an intelligent and resourceful girl who spends her time creating all kinds of inventions. She creates a robot, Kichinosuke, who follows her everywhere and becomes her close friend. She falls in love with Zero, a motorcycle enthusiast who prefers to travel the roads rather than study. Their mutual love of mechanical objects brings them closer together and Jun is determined to have Zero as her boyfriend. Unfortunately for Jun, he doesn’t even seem to notice her feelings!