Casshern desperately seeks to unravel the mystery of his dark past. An altercation with Dio, his robotic mirror image, could provide answers to his many questions - or at least get him killed.

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.

Casshern and his traveling companions befriend three children claiming to be descendents of Luna. When the youngsters are attacked by Leda, Casshern risks his own life to protect them.