At dusk, about to go home after playing with her friends, a young girl named Akane found a shadow without a caster. On that same day, she disappeared. Several years later, Ginko is told the story of Mikage, a girl who appeared with no memories at Akane's village shortly after the vanishing of the latter.

Izumi is alone in a world that mirrors our own. Having forgotten how she came to be there, she remains trapped while her family searches in vain. Her father believes she has been kidnapped, while her mother and sister Mizuho believe that she is still inside the house, even though they cannot see her. Ginko crosses into the other world to try to save her.