As alien invaders plot to conquer the Earth, two Boy Scouts steal a mini-submarine and discover Gamera in their midst. Transported to the alien's spaceship, the Scouts are menaced by the evil inhabitants, including Viras, a squid-like monster that grows to colossal size to battle Gamera.

Cast: Kōjirō Hongō, Tôru Takatsuka, Carl Craig, Michiko Yaegaki, Peter Williams, Kōji Fujiyama