Haunted by a recurring dream, young Madotsuki travels to another world every night. In this place, she faces a room containing 12 doors. Armed with curiosity and determination, Madotsuki sidelines her worries and voyages through these worlds, searching for the cause of their existence.

With each door hiding a unique theme, scenery, and dynamic, Madotsuki learns that the dream worlds are cunning and life-threatening. Will she resolve the mystery behind the 12 doors, or will she become bound to the dreamscape?