"You have one hour to live."
Those are the only words on the phone call. Then they hang up. Surely, a prank? A mistake? A wrong number? Anything but the chilling truth... That someone is watching, waiting, working to take your life in one hour.
The job of finding out falls to DI Helen Grace: a woman with a track record in hunting killers. However, this is A case where the killer seems to always be one step ahead of the police and the victims.
With no motive, no leads, no clues - nothing but pure fear - an hour can last a lifetime...