The Lunar Eclipse (月蝕, げっしょく gesshoku) was an event celebrated by the residents of Rougetsu Island every 10 years. A performance, the Rougetsu Kagura, was staged for tourists on the evening of the lunar eclipse. On the evening of September 17, 1970, however, two performances occurred simultaneously- the tourist ritual, attended by the public, and the "genuine" ritual, held in secret on a hidden stage underground. The underground ritual failed, and the five kidnapped girls serving as Kanade (Marie Shinomiya, Tomoe Nanamura, Misaki Asou, Madoka Tsukimori and Ruka Yomotsuki), or instrumentalists, collapsed and lost all memory of the incident. The mask of the Utsuwa, or masked dancer (Sakuya Haibara) split into multiple fragments and she too collapsed, and was confined in the basement of Rougetsu Hall in a coma-like state. The Utsuwa and Kanade from the tourist version of the ritual also collapsed; however, all six performers in this ritual died of heart failure.