In a futuristic world where robots co-exist with humans, a scientist creates a robot with incredible powers in the image of the son he lost.

Professor Leopold, who has appealed to stop a construction project that is destroying nature in the Basin Valley, fakes his own death; he tries to stop the construction wearing a cat mask as a disguise; Astro reveals his identity.

The Donohues and the Cavalets have been enemies for generations; their racing teams are rivals and their robot brothers are opposed to each other; Robio of the Donohues and Robiette of the Cavalets fall in love; Astro participates in the race.

A man-made solar sphere starts attacking the earth.