In the near future, an amnesiac Casshern fights anti-human robots on a desolate Earth. Most of the humans were killed in an apocalyptic war when he was serving under the direction of Braiking Boss after he assassinated a girl named Luna. During his quest to find out who he is, Casshern befriends a robot girl named Ringo. However, Ringo finds herself to be scared of Casshern after he kills a robot who was trying to attack her. Not long after, he faces against an anti-Casshern mercenary named Lyuze.