After the Vanguard High School Koshien, Kouji Ibuki is haunted by new nightmares. Suiko invites him to the mansion, revealing his ability to perceive a sinister Dark Tower named Sanctuary. This tower disrupts the timeline across ages, necessitating Kouji to rectify a forthcoming error. Joined by Suiko, they venture into the parallel world -if- where Magical Girls Emi Sendou and Shuka call upon Vanguard units to restore historical order. However, battling actual monsters proves futile in their quest for correction.