Ran-Sem: Hakudaku Delmo Tsuma no Miira Tori

At the center of this mysterious story is a secret club full of intrigue. It all starts with the disappearance of an attractive young woman named Anna in one of the Japanese cities. Her older sister, Riko, goes on a search and in the course of her investigations discovers a woman who claims that her man recently underwent initiation in this mysterious club and then disappeared without a trace.

Convinced of the seriousness of the situation, Rico decides to try to join this mysterious club in order to uncover the truth.