Labyrinth of the Blue Witch I.Minamiya-sensei along with Sasasaki, her colleague from the middle school, branch out into working vice on the trains. The two Witches of Ashdown, who are members of the criminal organization known as the Library, invade the island and wreak havoc. Yuuma Tokoyogi, Kojo's tomboyish childhood friend, flies in to visit after four years without contact. Along with his student friends, they take her to the tower of the Keystone Gate (キーストーンゲート) for sightseeing. There are strange occurrences around the city before its annual Halloween Festival. People begin teleporting when they pass through doorways and movement in the city is shut down by traffic mishaps. Astarte arrives at the tower to reveal that Natsuki has vanished and that her orders are to protect Kanon should this happen. That night, Yuuma speaks cryptically and at midnight, kisses Kojo and he falls unconscious. When he wakes, he finds himself in her body, with his own body now missing.