When Detective Lottie Parker receives news that a childs body has been found in the frozen grounds of the cathedral, a shiver runs down her spine. Shes terrified it will be eight-year-old Willow Devine, reported missing that morning. But when she arrives at the cathedral, she gets a terrible shock. The body is a young girl, wrapped in a white shroud, a rosary clutched in her frozen fingers. The girl isnt Willow but another eight-year-old, Naomi. Desperate to find a connection between the two girls and to find Willow before it is too late, Lottie speaks to the girls families and discovers that both girls were altar servers at the cathedral. The charismatic priest Father Maguire has a watertight alibi for the time the girls went missing, but Lottie suspects the confused old lady traumatised by the discovery of Naomis body is hiding something.