As the snow falls thickly on Newcastle, the shouts and laughter of Christmas revelers break the muffled silence. Detective Joe Ashworth and his daughter Jessie are swept along in the jostling crowd onto the Metro. But when the train is stopped due to the bad weather, and the other passengers fade into the swirling snow, Jessie notices that one lady hasn't left the train: Margaret Krukowski has been fatally stabbed. Arriving at the scene, DI Vera Stanhope is relieved to have an excuse to escape the holiday festivities. As she stands on the silent, snow-covered station platform, Vera feels a familiar buzz of anticipation, sensing that this will be a complex and unusual case. Then, just days later, a second woman is murdered. Vera knows that to find the key to this new killing she needs to understand what had been troubling Margaret so deeply before she died, before another life is lost. She can feel in her bones that there's a link.