Police officer Helen Weeks walks into her local newsagents on her way to work. It's the last place she expects to be met with violence, but she is about to come face to face with a gunman.

The hostage-taker is desperate to know what happened to his beloved son, who died a year before in youth custody. By holding Helen at gunpoint, he will force a re-investigation into his son's death. And one man knows the case better than any other - DI Tom Thorne.

As the body count rises, Thorne must race against time to bring a killer to justice and save a young mother's life.