An adaptation of Edogawa Ranpo's novel.

"We will never again emerge onto the surface. In this world, you and I are all humanity."
Early Showa era, Tokyo. A beautiful young man, Minoura, has a lover named Hatsuyo, who he is engaged to marry. One day, Hatsuyo is murdered by an unknown assailant. Minoura speculates that Moroto Michio, who had feelings for him in their school days, may have killed her out of jealousy. Moroto is a perfect man, smart and good looking, but he is a homosexual who is only interested in Minoura. For the sake of his beloved Minoura, Moroto devotes himself to cooperating with his detective work, but...?