Gaira, a humanoid sea beast spawned from the discarded cells of Frankenstein's monster, attacks the shores of Tokyo. While the Japanese military prepares to take action, Gaira's Gargantua brother, Sanda, descends from the mountains to defend his kin. A battle between good and evil ensues, leaving brothers divided and a city in ruins.
Kenji Sahara
Dr. Yuzo Mamiya
Kumi Mizuno
Akemi Togawa
Russ Tamblyn
Dr. Paul Stewart
Jun Tazaki
General Hashimoto
Kipp Hamilton
Singer
Yoshibumi Tajima
Officer Hirai
Nobuo Nakamura
Professor Kita
Hisaya Ito
Chief Izumida
