A robot comedy depicting the slapstick daily life of Mechatro 351, a robot with human-like emotions, and its master, high school student Yumeji, and his family. In the year 2XXX AD, on the spaceship Arcade, which was monitoring the orbital area of ​​a space colony where human beings migrated, the working robot Mechatro 351 began to behave strangely, enjoying a walk in space. And Mechatro 351, who was judged to have an electronic brain abnormality, was sold away to the colony's scrap shop...!?