The Secret Speech (Child 44 Trilogy 2) by Tom Rob Smith - Paperback
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.