This is the fourth Golden Age--style mystery (after The Mitford Scandal, 2020 to feature the six singular Mitford sisters and their ever-resourceful lady's maid, Louisa. The year is now 1933, and newlywed Louisa, studying stenography and settling into life as Mrs. Guy Sullivan, is recruited by MI-5 to keep an eye on the two fascist-leaning Mitford sisters who have fallen under the spell of Adolf Hitler. Louisa escorts Diana and Unity, along with their mother, Lady Redesdale, on an elegant Mediterranean cruise. Louisa's police-detective husband shows up to surprise her, but instead of enjoying a romantic tryst, they find themselves investigating a murder onboard while Louisa struggles to keep a sulking Unity, unhappy to be thwarted in a budding romance with a Nazi SS officer, in line. Inspired by the larger-than-life Mitford family and a real-life murder, Fellowes delivers a ripping-good read. Rich in detail, it moves steadily to its sad ending, leaving Louisa in possession of dark secrets that she will carry for the rest of her life.

In 1933, a few months after the Nazis take power in Germany, former Mitford family servant Louisa Cannon is approached by Iain, a British government agent, in bestseller Fellowes's subpar fourth Mitford Murders mystery (after 2020's The Mitford Scandal). Nancy Mitford, the eldest of the six Mitford sisters, recently offered to pay Louisa to accompany her mother and other family members on a Mediterranean cruise. Iain now asks her to accept Nancy's offer, because he wants her to spy on two Mitford sisters who have expressed support for the Nazis, notably Diana, who has been having an affair with English fascist Oswald Mosley. Louisa lies to her new husband, CID Det. Sgt. Guy Sullivan, telling him that she's going on the cruise to make some money. Guy ends up joining Louisa on the ship, where they're soon investigating a passenger's fatal bludgeoning. Flash-forwards to a murder trial with two defendants in 1935 inject some suspense, but this isn't enough to make up for an uninspired plot. Series fans will hope for a return to form next time. Agent: Caroline Michel, Peters Fraser and Dunlop (U.K.). (Jan.)

In Fellowes's The Mitford Trial, lady's maid Louisa Cannon is asked by a shadowy stranger to spy on Diana Mitford and her sister Unity, with someone ending up dead in the water when Louisa later accompanies the Mitfords on a cruise (75,000-copy first printing).