When a giant stone statue on Wester Island is disturbed, the legendary monster Jiger appears and heads for Japan. Gamera tries to stop this new rival, only to be injured when Jiger lays eggs inside of him. As two boys in a submarine go on a dangerous quest inside of Gamera's body to save him, Jiger threatens the Expo '70 world's fair in Osaka.
Tsutomu Takakuwa
as Hiroshi Kitayama
Kelly Varis
as Tommy Williams
Katherine Murphy
as Susan Williams
速水亮
as Keisuke Sawada
Franz Gruber
as Dr. Williams
八代順子
as Miko Kitayama
大村崑
as Ryosaku Kitayama
Umenosuke Izumi
as Gamera
Chico Lourant
as African Ambassador
夏木章
as Dr. Suzuki
