|The world is now ruled by a powerful robot leader, Braiking Boss, after mankind has been conquered by robots. The people summon a mysterious girl, Luna, to help them break away from the robots and bring salvation to the humans. In retaliation, Braiking dispatches three of his most powerful cyborgs to get rid of this potential threat. Casshern, one of the cyborg warriors, manages to kill Luna, thereby resulting in the gradual annihilation of the world.
Centuries later, mankind is on the brink of extinction. Casshern returns for the first time since he killed Luna. However, he has no memories of the past or who he is. In his search for his true identity, Casshern fights the robots to defend the humans.