This shocking novel depicts 15 years of forbidden romance between a father and daughter. In the summer of 1993 a massive earthquake rocked the island of Okushiri, off the west coast of Hokkaido, killing the other four members of nine-year-old Hana's family. She goes to live with her relative Jungo, a single man then aged 25 who turns out to be her father; the story traces her life with him until she turns 24, marries, and leaves.
The narrative begins in the year 2008, when Jungo shows up late to Hana's wedding with Yoshiro, a promising young man with a degree from an elite university. Returning to Japan from her overseas honeymoon, Hana decides to visit the rough apartment in the "lower city" on Tokyo's east side where she and Jungo had lived; there she finds that he has disappeared. From here the story goes back in time, piecing together the details of how the two came to be involved in their abnormal, intimate relationship.
Jungo's father, a fisherman, had died when Jungo was still young. When his mother fell ill, he went to live for a time on Okushiri, where his relatives ran an inn. There he became physically involved with Hana's mother; he was 16 years old when Hana was born. After coming of age Jungo joined the Coast Guard. When the earthquake struck he returned to the island, found Hana in one of the evacuation centers, and took her to live with him, nominally as his adopted daughter. Both all alone in the world, they became physically intimate, a relationship they would maintain for years. When Hana was 16 an elderly man discovered their incest and took a photograph proving it. Hana responded by killing him. The couple fled to Tokyo, where Jungo killed a detective who was pursuing them. Having both murdered for the sake of their love, they fell still deeper into mutual dependence . . .