When Chihiro was a baby, she suffered from eczema. Her parents tried to find a cure, but nothing worked. Her father's co-worker then gave him some water from a strange religious group. Chihiro was miraculously cured by the water. Her parents began to follow the strange religion and became fervent followers. Chihiro is now in the 3rd grade of middle school and she faces changes in her life.

Naito Naito, a second-year high school student who has the ability to survive in any situation, teams up with Ryuo Soya, a talented boy whose father is the head of the Ryuo Group conglomerate. Along with others, they challenge "Area Z," a game created by a genius known only as "Kurii Eita." Can they complete their mission to save the city within 6 hours? An original story based on the characters of Hayamine Kaoru's mystery novels.