After a slumber of twelve millennia, the Demon Empire awakens to seize control of the Earth. Raideen, the giant robot-like protector of the lost continent of Mu, senses the evil presence and awakens within its golden pyramid. A young Japanese boy, Akira Hibiki, is alerted about the Demon Empire by a mysterious voice and rushes to the pyramid. It is soon revealed that Akira is a descendant of the ancient people of Mu who must help Raideen save the Earth. Akira enters the robot by way of a ramp, accelerating his motorcycle into the robot's head and assuming control of Raideen from an internal cockpit. In typical anime style, Akira is aided by Mari Sakurano, who happens to be the daughter of a prominent scientist, and his friends from the soccer club. Half way through the story the Demon Empire's master, Barao, is released from his statue prison and intends to finish what he started twelve thousand years earlier.

Hisho, Ginga, Ace, Hayate, and Ikazuchi all work at a studio doing various idol-related jobs at the request of their manager, Reiko. But in reality, these five teenagers are really the Reideens, a group of superheros who fight the Super Devils sent by Lushu, a mysterious being. Little do the Reideens know, these Super Devils are being sent for a more important purpose....