The tensions caused by the Selector battles have seemingly dissipated, and the remaining participants have moved on from the ordeal quite rapidly. Nonetheless, Kiyoi Mizushima is of the belief that the conflict has yet to come to a close. Despite Kou Satomi's loss, his supporters continue to work behind the scenes to revive his plans. Mizushima's suspicions are soon verified, as the Selector battle system makes a reappearance, with the addition of a new mechanism. Players are now given special key cards, which can be unlocked with gold coins to unleash a hidden power. Cognizant of the formidable foes that lie ahead, Mizushima embarks on a quest to find skilled allies to aid her in putting an end to the cycle of darkness once and for all.