In Japan, a covert industry has grown up around the wakaresaseya (literally "breaker-upper"), a person hired by one spouse to seduce the other in order to gain the advantage in divorce proceedings. When Satō hires Kaitarō, a wakaresaseya agent, to have an affair with his wife, Rina, both assume it will be an easy case. But Satō has never truly understood Rina or her desires and Kaitarō's job is to do exactly that--until he does it too well. While Rina remains ignorant of the circumstances that brought them together, she and Kaitarō fall in a desperate, singular love, setting in motion a series of violent acts that will forever haunt her daughter's life.

In an engrossing dual narrative inspired by a true crime, Stephanie Scott exquisitely renders the affair and its intricate repercussions. As Rina's daughter, Sumiko, fills in the gaps of her mother's story and her own memory, Scott probes the thorny psychological and moral grounds of the actions we take in the name of love, asking where we draw the line between passion and possession.