Kojou comes out of the battle with his own body back, but both Yuuma and Natsuki have fallen. The true prison barrier has been revealed along with Yuuma's mother, Tokoyogi Aya, and the other magic criminals who were incarcerated within.

Kojou and company search for Natsuki, whose spiritual powers were stolen by Aya's grimoire and is now missing. Just then, Yukina's surprised voice directs the others' attention to the TV, where Asagi is seen on the live broadcast of the Halloween Fest...

Through Sana, Yukina sees a memory of Natsuki and Aya ten years ago, and then dreams of a happier world she shares with Kojou, Sayaka, and their friends.

Shortly after Yukina lost the use of Schneesturm Wolfin and received an order to return to the Lion King Organization, Itogami Island begins to fall apart under attacks from a magical beast that consumes dragon veins.

Natsuki magically prevents Kojo from leaving her premises. Kanon recruits Nina to spring him. Outside, Kiriha offers Yukina and him a private jet and false travel documents. Her agency is having fun at the expense of the rival Lion Kings. Asagi continues her efforts to leave the island with Mogwai's aid. Lydianne assists, and later the convict Meiga.

Kojo and the others go to rescue Asagi, who was imprisoned on the 0th floor of the Keystone Gate. Kojo is worried about Himeragi's poor condition, but Himeragi goes with Kojo nonetheless. What was waiting for Kojo and Himeragi on the 0th floor?

Kojo and the others are helpless by the power of Meiga Itogami's Cleansing ability. Kojo wonders what the hell this Cleansing ability is. At that time, the truth about the Cleansing is passed on to Kojo. Will Kojo be able to protect Himeragi and Itogami Island from Meigawa Itogami?!