The story begins in 1973, with the death of an Osakan pawnbroker, Yosuke Kirihara, under strange circumstances. The investigation, headed by officer Junzo Sasagaki, gradually uncovers Fumiyo Nishimoto, a mother struggling to make ends meet and one of his customers, and her boyfriend Tadao Terasaki, as prime suspects. However, the Osakan police are unable to definitely prove their involvement, and both are eventually found dead; Fumiyo dies in an accidental gas leak in her house, and Terasaki dies in a traffic accident. The story primarily concerns itself with the effects of this incident on two people: Ryoji Kirihara, the pawnbroker's son, and Yukiho Nishimoto, Fumiyo's daughter. The novel avoids directly revealing the two's thoughts to the reader, instead preferring to reveal information second-hand through the viewpoints of multiple other supporting characters whose lives intersect to form a complete picture of the story's events.
Ryoji ends up growing into a moody, sullen and cynical youth who gets involved in a number of shady dealings, such as housewife prostitution rings, computer game bootlegging, hacking corporate programs, and wiretapping. He is shown to be resourceful and intelligent, easily manipulating people into doing what he wants. The novel strongly suggests that he commits multiple murders, including Isamu Matsuura, a former employee of his father's shop who he assists in a videogame bootlegging scheme. These murders force him to assume fake names and run from the police.
Yukiho is adopted by a relative of her father's (changing her last name from Nishimoto to Karasawa) and matures into a beautiful upper-class woman, attracting the attention of multiple men and achieving success in different fields, such as stock trading and opening up a successful clothing store chain. However, many people connected to her suffer from incredible misfortunes, and several characters in the narrative note that there is a hidden dark side to Yukiho hidden beneath the surface.
Throughout the story, Sasagaki shows up multiple times, unable to let go of the unresolved murder and determined to find the truth, even after the case passes the statute of limitations. Twenty years after the incident in 1992, he is finally able to piece together the truth: Fumiyo Nishimoto was prostituting her daughter to Yosuke Kirihara in order to pay the bills, explaining the interest displayed by Yosuke towards the family in the beginning of the story. Ryoji, who was Yukiho's friend, became suspicious after seeing her with his father and followed them to an abandoned building, where he witnessed Yosuke molesting her. In his grief, he killed his father with a pair of scissors. In turn, Yukiho killed her mother by drugging her with sleeping pills and causing a gas leak in her house. Ryoji and Yukiho then developed a close relationship of some sort in order to cope with their grief, using their talents to achieve success and ruthlessly disposing of anyone who got in their way.
Towards the novel's end, Sasagaki is able to obtain evidence linking Ryoji to Matsuura's death. The police wait for him to appear at the opening of Yukiho's second shop on Christmas Day, and discover he is one of the employees dressing up as Santa Claus. Cornered, Ryoji runs to the top of the building and jumps to his death. When asked, Yukiho denies knowing him.
