In ancient times, the Mecha Empire Sharmachina, which ruled the Earth with advanced technology, was sealed deep within the Earth by Garkibas, a brave warrior of the Kaiju Clan. However, affected by climate change, the seal has weakened, and the empire has begun to rampage across the surface once again. The souls of these Kaiju Clan warriors—the heroes of Earth—entrust their powers to five young people. Becoming the Kaiju Sentai Jyuukaizer, they valiantly stand against Sharmachina alongside their Buddy Kaiju!