Katsumata Masaru is a high school student who is beaten every day by his daughter who lives next door, Chodenji Youyo. One day, the two find the key to the laboratory of Youyo's late father, who was an authority in the field of robotics, and enter the room. Among the many unidentifiable inventions, they discover a beautiful robot girl, SPN01. When Masaru unintentionally touches her breasts, 'she' suddenly starts up...