Mako, a life insurance saleswoman, struggles to improve her performance and faces constant reprimands from her manager, Koizumi. One day, she runs into Isao, a boyfriend from her student days. Through an introduction from Koizumi, she visits Murayama—a man who has made a fortune in illegal lending—and is forced to offer her body in exchange for securing a large insurance contract. Meanwhile, Isao, who works at a detective agency, discovers that Murayama was involved in the incident that drove Mako’s mother to suicide. Upon learning this, Mako begins to harbor murderous intent toward Murayama...