In the darkest hours of World War II, Doreen Valiente, an expert of British folklore and the occult, is approached by British intelligence who tell her they know she's a witch ... and that's how she can best serve her country. Together with 'the most evil man in the world,' a hard-nosed white witch, the grizzled founder of Wicca, and a professional exorcist and con man, Valiente will travel deep into the heart of Nazi-occupied Europe and gamble her life, her belief, and her powers on a mission to help capture Rudolf Hess, second in command to Adolf Hitler himself.