London, the Blitz, Autumn 1940. As the bombs fall on the blacked-out city, ambulance driver Elinor Brooke races from bomb sites to hospitals in order to save the lives of injured survivors. She works alongside former friend Kit Neville while her husband, Paul Tarrant, works as an air-raid warden. Into their midst comes the spirit medium Bertha Mason, grotesque and unforgettable, whose ability to make contact with the deceased finds vastly increased demand as death rains down from the skies. And as old loves and obsessions resurface, Elinor is brought face-to-face with an almost impossible choice.