Being held hostage at gunpoint by her childhood friend is not Dr Heather Gilmore's idea of a good day at work. It only gets worse when she hears that her daughter, Leah, has been kidnapped. Sergeant Claire Boyle is put in charge of finding the missing girl, and it soon becomes apparent that the kidnapping is somehow linked to the hostage-taker, a woman called Eileen Delaney. But what happened between Eileen and Heather to make Eileen so determined to ruin her old friend?