On his way back to his home planet after completing his mission, the steel giant Yarusenaizer collides with a meteorite and crashes down to Earth. Being badly damaged by the crash, Yarusenaizer can't go back to his home planet until his repairs are fixed. Taking pity on him, the protagonist, Amanogawa Seiji, takes him to live with him. Like that, the story opens! But in the small Japan, it's not easy for a giant robot; many problems face him!