Michio Yoshida is an unremarkable salaryman toiling away at a third-rate advertising agency, his life defined by monotony and dull routine. That existence is violently upended when he becomes possessed by Mako and Seiko, two beautiful and bewitching twin sisters whose true nature remains a mystery. The story follows Michio as his world is flipped upside down, and in several other positions, as he finds himself cruelly toyed with by this pair of sirens, beginning a series of naughty, devilish delights that make his life a hellish heaven.

Set in the early 1990s in a mundane, contemporary Japanese city, the narrative contrasts the boring everyday reality of a white-collar worker with the supernatural and erotic chaos the sisters bring. The primary conflict is not a battle against a great evil but an internal and physical struggle as Michio is caught in the web of Mako and Seiko, whose motives and identities are ambiguous. As a one volume work originally published in 1991, its single, extended narrative arc focuses entirely on this twisted relationship. From the moment of possession, the story follows the escalating, erotic torment of the protagonist as he is dominated and enchanted by the two sisters, exploring the boundaries of his sanity and endurance within this surreal, adult fairy tale.