The Crime: The customers in a London convenience store are taken captive. Among them is a young mother, Detective Helen Weeks. She is told her life depends on the co-operation of one of her colleagues - detective Tom Thorne.

The Demand: Akhtar is desperate to know what really happened to his beloved son, who died a year before in prison. He is convinced the death was not an accident and forces the one man who knows more about the case than any other, Thorne, to re-investigate.

The Twist: What Thorne discovers will upend everything he thought he knew about the fate of those he's put away... but will it be enough to fulfill the wishes of a grieving and potentially violent father?