Why would the world's most famous mystery writer disappear for eleven days? What makes a woman desperate enough to destroy another woman's marriage? How deeply can a person crave revenge? In 1925, Miss Nan O’Dea infiltrated the wealthy, rarefied world of author Agatha Christie and her husband, Archie. In every way, she became a part of their life––first, both Christies. Then, just Archie. Soon, Nan became Archie’s mistress, luring him away from his devoted wife, desperate to marry him. Nan’s plot didn’t begin the day she met Archie and Agatha. It began decades before, in Ireland, when Nan was a young girl. She and the man she loved were a star-crossed couple who were destined to be together––until the Great War, a pandemic, and shameful secrets tore them apart. Then acts of unspeakable cruelty kept them separated. What drives someone to murder? What will someone do in the name of love? What kind of crime can someone never forgive? Nina de Gramont’s brilliant, unforgettable novel explores these questions and more.