The Soviet Union 1956: after Stalin's death, a violent regime is beginning to fracture. Stalin's successor Khrushchev pledges reform. But there are forces at work that are unable to forgive or forget the past. Leo Demidov, former MGB officer, is facing his own turmoil. His adopted daughters have yet to forgive him for his part in the brutal murder of their parents. They are not alone. Leo, his wife, and their family are in grave danger from someone with a grudge. Someone transformed beyond recognition into the perfect model of vengeance. Leo's desperate mission to save his family will take him from the harsh Siberian Gulags, to the depths of the criminal underworld, to the centre of the Hungarian uprising - and into a hell where redemption is as brittle as glass.