War with Germany is looming, even as civil war rages in Spain—and split across political lines, the six Mitford sisters are more divided than ever. Their former maid Louisa is now a private detective, working with her husband Detective Sergeant Guy Sullivan, and in this fifth mystery (after The Mitford Trial), a call comes in from novelist Nancy Mitford requesting that they look into the disappearance of her sister Jessica, who was with the communists in Spain. Louisa and Sully are also tracing a soldier's disappearance, and as the two cases come together, they find that every marriage has its secrets—but some are more deadly than others.