The peaceful days turn out to be short-lived as the shadow of another Selector Battle looms large. Mizushima Kiyoi is the first to notice that things are amiss, and she makes her move to put an end to the cycle of darkness.The Battle this time includes a new card, “Key,” and has been set up with rules different than before. With both the mastermind and their motive shrouded in mystery, the darkness grows ever deeper and more menacing. Homura Suzuko, Morishita Chinatsu, Mikage Hanna, Kominato Ruuko, Kurebayashi Yuzuki, Uemura Hitoe, and Aoi Akira… The Selectors gather once again. Hopes, memories, and the key… The final battle with everything on the line begins now!