After Otoya is knocked out during his fight with Jiro, Yuri recovers the IXA Knuckle and plans to track down the man who murdered her mother. But when she faces the man, she is swiftly knocked out as Jiro arrives and also recognizes him… as the man who slaughtered the Wolfen race. He is Rook, of the Fangire’s Checkmate Four! Meanwhile, in 2008, Wataru and Shizuka encounter Rook, who seems to be suffering from amnesia…

As Wataru and Shizuka try and help Rook, who they’ve nicknamed “Biggie”, recover his memories, he begins spending time with a young woman whose bike he helped fix. Their hope is this might jog his memory. Meanwhile, Jiro proposes an alliance with Otoya to take down Rook and protect Yuri, and Otoya tenuously agrees…