Do things cease to exist if we forget about them?
For every decade, a special ceremony is held at a shrine in Oborotsuki island. 10 years ago, during a traditional Japanese concert, a case of suspected abduction occurred. Five girls disappeared without a trace as if taken away by supernatural forces.
Although the case was solved by a policeman, the girls seemed to have suffered from a special form of amnesia, they have forgotten what happened during their abduction. The amnesia disturbed the girls, but this matter seemed to have been settled when they moved away from the island.
However, unlike what everyone thought, this case was not over. 10 years later, two victims from the case were killed in a brutal manner and the survivors suspected it has something to do with Oborotsuki island. To find out about the truth behind the case and stop the killing before the culprit takes another life, two survivors, Misaki and Madoka set off to the island they have moved away from so long ago.
The remaining survivor Minatsuki Ruka seemed to be the only one who still retained some remnants of memories from her abduction ordeal. She remembered a melody, a group of musicians being surrounded by a circle of masked men and a masked woman who danced as if she was possessed by spirits. In search of the truth behind the memories and images that plagued her life, she, too set off for the island after Misaki and Madoka.