Braiking Boss has established a robot kingdom in the world. However, a girl named Luna emerges, and the human race sees her as their salvation. In response to this emerging threat, Braiking Boss sends his three strongest robots: Casshern, Dio, and Leda... Only Casshern reaches Luna and kills her, but her death brings destruction to the world. Centuries pass, and Casshern reappears. However, the robots believe that by killing Casshern, they can escape rust and death. Casshern, who remembers nothing of his past or himself, embarks on a journey to discover his history and purpose.
