Prince TATA from Planet BT, who had been traveling with VAN, crashed on Earth. In order to spread love, TATA decides to become a star. Finally, they have met six fascinating members: KOYA, RJ, SHOOKY, MANG, CHIMMY, and COOKY to make 'BT21', and they are dreaming of becoming the most famous start in the universe, THE UNIVERSTAR! Will BT21 become UNIVERSTAR, and spread love around?