Kaixin Baobei

On the technologically advanced Planet Xing, Doctor H discovers four mysterious mechanical stones and uses them to repair a group of damaged vehicles. The stones awaken as robot heroes: Happy S, Sweet S, Smart S, and Careless S, each with a very different personality but the same instinct to protect their home.

Meanwhile, Big M and Little M of Planet Gray continue their efforts to conquer Xing, using a dark stone and increasingly bizarre schemes to create trouble. The four heroes must learn to work together, balance daily life with sudden emergencies, and stop the invaders before their plans turn the cheerful planet into their next possession.