Jun is a highly intelligent young girl who spends her time arranging various inventions. This activity leads to the creation of two small robots, Kichinosuke and Yukinojo, who become her best friends. Due to her intelligence, Jun enters college at a young age, where she meets and falls in love with a classmate named Zero. Zero is interested in motorbikes rather than school and is accustomed to skipping classes. He fell behind in his schooling, making him much older than the other students, and he is humiliated for this. Conversely, Jun is far too young and small for college and is made fun of. Thanks to their shared passion for mechanics, Zero sympathizes with Jun and agrees to dine with her at Harbor, the restaurant where Jun's parents live. This is a long series of fun adventures and arguments that little Jun undertakes to allure her charming prince, who is twice her age.