Ada's mother is so ashamed of her daughter's club foot that she doesn't let nine-year-old Ada leave their apartment. Ada's only information about the world outside comes from her little brother, Jaime, and from tidbits overheard at the window, such as news of the approaching war. When London plans an evacuation of the city's children to safer spots in the country, Ada dares to escape her abusive mother and join Jaime on the train out. Then, they meet Susan Smith, a reclusive woman who takes them in. Little by little, Ada opens up and starts to trust people, and Susan learns to nurture the kids and to love again after years of loneliness.