Its the week before Christmas when a lone robber bursts into a busy Glasgow post office carrying an AK-47. An elderly man suddenly hands his young grandson to a stranger and wordlessly helps the gunman fill bags with cash, then carries them to the door. He opens the door and bows his head; the robber fires the AK-47, tearing the grandfather in two.Detective Alex Morrow, just returned to work after the birth of her twins, arrives on the scene and finds that the alarm system had been disabled before the robbery, but none of the employees can be linked to the gunman. The grandfathera life-long campaigner for social justiceis above reproach. As Morrow searches for the killer, she discovers a hidden, sinister political network. Soon it is chillingly clear: no corner of the city is safe, and her involvement will go deeper than she could ever have imagined.