When Geraldine Bretherick and her 5-year-old daughter Lucy are found dead in the bathroom of their luxury home, the case divides new DS Charlie Zailer and her DC Simon Waterhouse. Is it a murder-suicide or something even more sinister, and how watertight is the alibi of the apparently distraught husband Mark? Meanwhile, when Sally Thorne, a young working mother with a husband and two small children hears of the deaths, she is deeply shocked. Months before she'd met a man called Mark Bretherick at a hotel and they had a brief but passionate affair. Now, against the advice of her best friend, Esther, Sally feels the need to get in touch with Mark again to offer her sympathy.  Based on the bestselling novel The Point of Rescue by Sophie Hannah, this psychological thriller explores the darker side of motherhood, identity and love.