The Mitford Secret

In Fellowes’s strong sixth and final mystery centered on the real-life Mitford family (after 2021’s The Mitford Vanishing), private detective Louisa Sullivan, the family’s former nursemaid, reunites in 1941 with the Mitfords at Chatsworth, their new home in the English countryside, which serves as a refuge for Louisa and her five-year-old daughter from the bombing of London. Then an old woman appears at Chatsworth, Mrs. Hoole, who claims to have a message for the youngest Mitford sister, Deborah, from the other side, directing Deborah to search the house’s vestibule. Those in attendance go along with the request, and Louisa finds a bloodstained maid’s cap hidden behind a wall panel. Mrs. Hoole eventually reveals the cap’s connected to the disappearance and likely murder of Joan Dorries, who was in service with her and vanished more than 25 years earlier. A fresh murder, which seems clearly linked to Joan’s fate, injects even more life into the cold case. Fellowes neatly balances period detail and fair cluing. Fans will be happy to see this series going out on a high note. Agent: Eugenie Furniss, Peters Fraser and Dunlop (U.K.). (Jan.)