R is the other woman. Labelled simply with one initial, her identity in the famous 1940s novel that recounts the damage she did to her lover's family remains shrouded in mystery. The novelist who carried out an illicit relationship with her, and then used her as material for his work, became a celebrated writer. But R never had the chance to put her side of the story.

Tamaki is determined to find out who R really was. A writer herself, she is working on a book about R and begins to uncover clues about the real story behind the novel, and the great tragedy of the novelist's life. While she throws herself into her research she's aware that her own imperfect relationships are also up for scrutiny. Her ex-lover, Seiji, is gravely ill in hospital and her reminiscences about their long affair strike echoes with the subject of her work.

In this compelling and moving novel, prize-winning author, Natsuo Kirino explores the themes of love and death, and the significance of fiction.