On his way to spar with Ultraman Blazar, Beliarok runs into Ultraman Zero. Zero refuses Beliarok's challenge to fight saying it would bring back bad memories of his fated nemesis and the battles he fought against him. However.

Zero and his friends arrive on the Planet of Mirrors they learned of from Glenfire. There, they find a miserable sight. The noble Mirror Knight has fallen prey to Belial's darkness.