A can’t-believe-it’s-true wartime binge that tells the incredible story of a mother, the son she was forced to give up for adoption, and the spy who, decades later, infiltrated her life with a devastating lie.

Johanna van Haarlem never wanted to abandon her son, Erwin. But the Nazis had occupied Europe and the teenager felt she had little choice. Her father had kicked her out, telling her she could return, without the child—or not at all. Johanna realized that together, she and her newborn wouldn’t survive; separated, at least Erwin had a fighting chance. So she surrendered the baby to an orphanage and tearfully went back home, vowing to return for Erwin one day.

Johanna lives to see the Nazis defeated, and to deeply regret abandoning her child. When, decades later, at the height of the Cold War, she receives a letter from Erwin, it feels like a miraculous second chance. But at their joyful reunion in London, Johanna makes a disturbing discovery: Erwin’s eyes are the wrong colour. In a decision that will come to haunt her, she quickly buries the seed of her doubt and welcomes the young man into her life.

It will take more than a decade for the imposter’s deceit to come to light, even longer to untangle the lies shielding his real identity—and his motives. Unfolding in a series of astonishing twists and turns, A Spy in the Family reveals the true story of a notorious Soviet Bloc agent who took advantage of a mother’s heartbreak to hide in plain sight.