Jonathan and his identical twin brother, Charles, are obstetricians who share a thriving practice in Manhattan. Even Jonathan's wife Olivia, a psychologist, has difficulty telling them apart. When Charles is found murdered in his midtown apartment, Olivia helps her husband mourn the loss of his twin- until, as the months pass, she begins to suspect that it was not Charles who was killed, but her husband Jonathan. Her search for the truth plunges her into life-threatening danger. Clark's stunning new novel explores the family ties that bind, and what evil forces may break them.