When Detective Lottie Parker receives news that a child's body has been found in the frozen grounds of the cathedral, a shiver runs down her spine. She's terrified it will be eight-year-old Willow Devine, reported missing that morning.
But when she arrives at the cathedral, holding a photo of Willow with her blonde ponytail and gap-toothed smile, she gets a terrible shock. The body is a young girl, wrapped in a white shroud, a rosary clutched in her frozen fingers. But her hair is dark, not fair. This girl isn't 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 Naomi's body is hiding something...
A day later, Willow's little body is found wrapped in a white robe in the snowy grounds of a church across town. Lottie is devastated, convinced now that she can't trust anyone, least of all the girls' parents. Why did Willow's mother claim the girls didn't know each other? And why are there no photos of Naomi in her mother's shabby house?
But when a little boy from the choir goes missing too, Lottie realises she must spread her net wider. Can she stop this twisted killer before another precious life is stolen?