As the story begins, Rika Umezawa is traveling in Chiang Mai, Thailand. Her embezzlement of some 100 million yen has come to light, and she is on the run. The story then steps back in time to 1990, when she first started working for a suburban Tokyo bank as a part-timer, and follows the twists and turns of her life over the next 12 years. Born into a family of means and raised with a strong sense of right and wrong, she had taken the conventional path from college, to job, to marriage at 25 and becoming a housewife. She and her salaryman husband now live a frugal life. But unable to conceive a child and bored with staying at home, she decides to go back to work. She finds that she has a way with the elderly customers in particular, and receives excellent reviews for attracting many new deposits. In 1994 she accepts a promotion to full-time contract worker. Shortly thereafter, when visiting client Hirabayashi, one of her biggest fans, she meets his grandson Kota, and it sets off a sequence of events that utterly transforms her life.
Since returning to work, Rika has enjoyed having funds of her own to spend, but her failure to bear a child has led to a sexless marriage. Now she begins an affair with Kota, and when she learns that he has incurred large debts with a consumer lending company to pay tuition and finance his amateur film endeavors, she conceives of a scheme?forging fake certificates of deposit?that enables him to surreptitiously "borrow" the money from his grandfather's accounts and close out his high-interest debt. Soon she is doing the same with other customer accounts to finance her weekend vacations with Kota in luxury hotels, their love-nest apartment, a car for Kota, and her own extravagant shopping and spa excursions. As things spin out of control and she no longer knows how much she has misappropriated, she discovers that Kota has a girlfriend . . . In relentless detail, the author probes the psychological forces by which an ordinary, upstanding housewife loses her moral compass and digs herself into a deeper and deeper hole of crime.