When Saburo goes mountain climbing with Tokimura, a member of the Global Safety Project, they are entangled in a snowslide. Saburo then witnesses a huge mechanism in a misty valley, bringing to mind news about the Brain which suddenly disappeared after completion several years ago.
The Brain is still alive and the mechanism uses its own army of giant robots to protect itself from men.
Fleeing from the Brain, Saburo encounters another robot and removes the magnetic filter that had been controlling it. This robot, called DAITETSUJIN 17, gives Saburoa helmet containing a communication device. Hand in hand with the Global Safety Project, they fight the enemy troops of robots and other villains that the Brain is now using in his attempts to conquer the world.
