The young Prince of planet Fleed flees his destroyed homeland aboard the UFO Robot Grendizer. On Earth, aided by a scientist and allies, he battles Vega's forces sent to capture Grendizer and conquer or destroy the universe.

Escaping from Vega's evil forces, the young Prince of planet Fleed leaves his destroyed homeland aboard the UFO Robot Grendizer, a powerful war machine, and makes it to Earth. Rescued by a bright scientist and fellow earthlings, he fights the saucers and robots sent by Vega, who plans to seize the mighty Grendizer and conquer the whole universe, or destroy it either.—Luis Pero