After a slumber of 12 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.  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. Raideen was able to transform into a robotic eagle.