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.
本郷功次郎
as Scout Master Mr. Shimida
Tôru Takatsuka
as Masao Nakaya
Carl Craig
as Jim Morgan
Michiko Yaegaki
as Mariko
Peter Williams
as Dr. Dobie
藤山浩二
as Self-Defense Force Commander
渥美マリ
as Junko Aoki
八代順子
as Masako Shibata
北原義郎
as Masao's Father
Munehiko Takada
as Jim's Father
Mary Morris
as Jim’s Mother
橋本力
as Doctor 1
