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.
Kōjirō Hongō
Tôru Takatsuka
Carl Craig
Michiko Yaegaki
Peter Williams
Kōji Fujiyama
Mari Atsumi
Junko Yashiro
Yoshirō Kitahara
Munehiko Takada
Mary Morris
Chikara Hashimoto
Kenji Go
Shō Natsuki
Ken Nakahara
Kenichiro Yamane
Genzô Wakayama
Teruo Aragaki