A young woman wakes in a cold, dark cellar, with no idea how she got there or who kidnapped her. So begins her terrible nightmare.

The body of another young woman is discovered buried on a remote beach. But the dead girl was never reported missing - her estranged family having received regular texts from her over the years.

For DI Helen Grace it's chilling evidence that she's chasing a twisted monster who is clever and resourceful - a predator who's killed before.

As Helen struggles to understand the killer's motivation, she relaises she's in a desperate race against time...