During the 1970's, five girls were kidnapped on Rogetsu Isle to be an unwilling participant in a secret Rogetsu Kagura performance.
The girls were taken by Yo Haibara to be used as Organs during the rite. All of the girls suffered from Moonlight Syndrome. The Rite of Descent had failed and the girls collapsed, losing all their memories. For two weeks the girls were left in the underground Moonglow Cavern where they were observed by Shigeto Haibara. However, they were discovered by detective Choshiro Kirishima who was assigned to find them.
10 years later, two of the five girls, Tomoe and Marie were found dead under strange circumstances. Their faces contorted in horrified expressions, similar to the deaths of the islanders years before. Determined to find answers and avoid the same fate, Misaki and Madoka traveled back to Rogetsu Isle. Following suit was Ruka, hoping to find her own answers about her past and Choshiro Kirishima, who was sent by Sayaka, Ruka's mother, to bring her back home.
The girls were said to be "spirited away", although they were later found. Those who are considered spirited away are assumed to be kidnapped by spirits, and due to the strange circumstance of their disappearance and the disastrous events that followed, it's believed the island inhibitors meant this more spiritually than physically.