Yapool, an ancient interdimensional race of beings tries to conquer the Planet Earth with his army of monsters, called Terrible-Monsters. The newest member of the Ultra Brothers, Ultraman Ace, arrives on Earth to aid humanity in the battle against Yapool. Touched by the sacrifices of Seiji Hokuto and Yuko Minami, he revives them and grants them the Ultra Rings, which allows them to transform into Ultraman Ace in times of need.

Keiji Takamineas Seiji Hokuto
Gorō Nayaas Ultraman Ace (voice)
Mitsuko Hoshias Yuko Minami
Tetsurō Sagawaas "Devil" Captain Goro Ryu
Mahito Tsujimuraas Ultraman (voice)
Osamu Sakaas Ultraseven (voice)
Keisuke Yamashitaas Ultraman Jack (voice)
Toru Fuyuki