A letter gets delivered to Jino, the champion of Hero's Cup. It was an inviation to the Ultimate Watch Car Battle League that is notorious for its brutality. On the day of the UWB, Bluewill, Jino's Watch Car, is kidnapped by strangers on the way back home from the UWB but in the end he is recovered.
Jino hides his identity and along with Bluewill who disguises himself as Bluethunder, participates in UWB to stop their scheme.
Will Watch Car be able to become the new hero of UWB?