百年ぶりとなる最大級の皆既月食を明日に控え、白いドレスの女が獣人に襲われるという事件が相次いでいた。民俗学研究室の尾形（高野八誠）は、百年前の皆既月食の年、やはり同じ獣人事件が起きていたことを伝える。鷺ノ宮家令嬢のまひる（中村果生莉）が襲われた夜、同家に滞在していた異邦人・望（小笠原宙）が失踪したことに関係があるのか！？百年前に消えたはずの双眼鏡に映ったのは赤い月と・・・！そしてついに皆既月食が始まる！
With the biggest total lunar eclipse in a hundred years approaching tomorrow, there have been a series of incidents of women in white dresses being attacked by beastmen. Ogata from the folklore research lab tells us that the same beastman incident occurred a hundred years ago, the year of the total lunar eclipse. Could it be related to the disappearance of Nozomi, a foreigner staying at the Saginomiya family, on the night that Mahiru, the daughter of the Saginomiya family, was attacked? A red moon is captured in the binoculars that were supposed to have disappeared a hundred years ago...! And finally, the total lunar eclipse begins!
