Narrator Saburo Sugimura, 35, works on the in-house magazine of the Imada Concern, one of Japan's largest industrial conglomerates. Seven years ago he married Naoko, 29, a love child of Yoshichika Imada, 79, founder and current chairman of the Concern. They have a four-year-old daughter, and lead a comfortable life together.
One day, Saburo's father-in-law asks him a favor. His longstanding driver, Nobuo Kajita, 65, has died as the result of a hit-and-run bicycle accident on August 15. Kajita's wife predeceased him by five years, and he leaves behind two grown daughters—Satomi, 32, and Riko, 22. Yoshichika wants Sugimura to meet with them and see if he can be of assistance. The sisters say they'd like his help, as a former book editor, in putting together and publishing a biography of their father. Since the hit-and-run cyclist who killed their father remains at large, the objective is to spread word about the incident in hopes of turning up new information that could lead to his arrest. Riko is the enthusiastic one, while Satomi, who is engaged to be married in October, seems decidedly more tepid to the idea. As the older sister by ten years, she recalls a few things about the period before their father became a driver, when he had to move from job to job and they lived a life of considerable privation, and she's not eager to have details come out. In particular, she reveals to Sugimura that she remembers being kidnapped when she was about four years old, and says that she suspects it has something to do with the hit-and-run that has killed her father. With little to go on, Sugimura turns impromptu private eye and starts digging to see what he can find out . . .
Twenty-eight years ago, Kajita and his wife were working at a toy factory, where they had a younger colleague named Yuko Nose. Yuko's father was prone to violence when he got drunk, and she accidentally ended up killing him. Feeling sorry for her, Kajita and his wife offered to take the body somewhere far away and bury it. While they were gone, they left the young Satomi with Yuko. . .
As the plot twists and turns to reveal that the cyclist who caused the accident was a seventh-grade boy riding at a reckless speed, and that Satomi's fiancé has been on intimate terms with Riko, the reader is given much to ponder about family bonds, about the potentially lifelong consequences of our mistakes, and about both the goodness and evil that reside in the human heart. Sugimura has subsequently returned as the protagonist of Na mo naki doku (Nameless Poison, 2006) and Petero no soretsu (Peter's Funeral Procession, 2013).