Casshern awakens to find his world reduced to a corrosive wasteland. Lost in a future he does not recognize, he struggles to stay a step ahead of those who wish death upon him.

An encounter with the mysterious Lyuze offers Casshern a fragmented glimpse of his role in the Ruin. After stumbling upon a community of “dying” robots, he discovers the true depth of his infamy.

Dio’s mission to assemble a robot army is interrupted by the appearance of Dune, a formidable warrior who was once Luna’s bodyguard. Elsewhere, Casshern continues his search for Luna.

Dying robots far and wide herald the saving grace of Luna. Meanwhile, Lyuze is disturbed to notice that Ringo has begun to rust, and Casshern is confronted by the monster who ordered him to Ruin the world.

Leda tries to convince Dio to accept Luna’s healing, but eternal life is no longer his obsession. Dio now lives only to fight Casshern - even if their battle ends in his own destruction.

Casshern and Dio continue their epic final battle. Although only one will survive, they’ve embraced the chilling reality that fighting is the sole purpose of their tragic existence.

Casshern and his friends enjoy the peace of their new lives until the Ruin destroys their happiness. Driven by grief, Casshern sets out to settle the score with Braiking Boss - and issue a warning to Luna.