Gretel Fernsby is ninety-one years old and has been living in London for decades. She has a comfortable, quiet life, despite her dark and tumultuous past. She doesn't talk about her escape from Germany over seventy years ago; she doesn't talk about the post-war years she spent in France with her mother, but mostly she doesn't talk about her father, the commander of the most notorious concentration camp.
And then, she moves into the apartment below her own a new family. Although she doesn't seek it, Gretel develops a friendship with their little boy, Henry, and one evening, she witnesses a violent argument between his mother and his domineering father.
Gretel is faced with the opportunity to free herself from guilt, sorrow, and remorse, and to act in order to save a little boy - for the second time in her life. But in order to do this, she will have to reveal her true identity to the world. Will she be able to make a different choice this time, no matter the cost to herself?