Plot: 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