In Edwardian Britain, Lady Adelaide Azalea Margaret de Morville, Mrs. Hugh Becket, finds her work for William Melville, spymaster, clashes with the life her society friends believe her to be leading. Her guilt rises when her very dear friend, Isa Hass, arrives from Cape Town and asks questions Adele cannot answer. When a homeless urchin, Charlie Rowbottom, hands a note written in German code over to Adele, she struggles to keep her true nature separated from her position in society while she searches for the writer of the note.