Long ago, a powerful sentient robot known as GoLion, abused his great powers by attacking and killing creatures known as Deathblack Beastmen, boasting that no one could defeat him. For his arrogance, The Goddess of the Universe punished GoLion by separating him into 5 different lion robots. In the year 1999, a group of 5 young men returned to Earth after a space voyage, only to find it ravaged by nuclear war. After encountering the alien race known as the Galra, the 5 youths end up on the planet Altea and learn that the 5 lion robots that GoLion was split into are in hibernation in various parts of Altea. Somehow, they must reunite the lions and form GoLion, the only hope for the human race.

To the empire, Prince Arnold is one big joke, a completely inept prince outshone by his more talented twin, Leonard. But in secret, Arnold operates as Silver, one of only five magic-wielding SS-rank adventurers on the continent. As the bloody battle for the throne intensifies after the crown prince’s death, Arnold pulls the strings from the shadows to crown his twin emperor to his own advantage.