A rescue team is sent to Mars to bring back an astronaut who claims that a Martian monster killed his team. As they return to Earth, they sense the presence of the creature in the spaceship.
Ben Harris and Harold Tufnell-Jones are rescuers and British nationals who do their best to rescue a woman from Sir Hugh, the captain of an underwater establishment.
A warship that can navigate land, sea, and air becomes Japan's last defence against an ancient underwater civilisation bent on reclaiming the surface world.