Christmas Eve, 1938. Madge Arwell comes to the aid of an injured Spaceman Angel, who promises to repay her kindness – all she has to do is make a wish. Three years later, Madge escapes war-torn London with her two children for a dilapidated house in Dorset. Crippled with grief at the news her husband has been lost over the English Channel, she wishes to give her children the best Christmas ever. The Arwells are greeted by the Doctor, who acts as their madcap caretaker. However, a mysterious Christmas gift from him leads them into a wintry, magical world. Madge must learn how to be braver than she ever thought possible and that wishes can come true.