A Presumption of Death
Jill Paton Walsh
 Harriet has evacuated her family to the Wimseys' country house, Talboys (in Hertfordshire), taking her two children, along with the three children of her sister-in-law, Lady Mary, and Peter's venerable old housekeeper, Mrs. Trapp. Peter and Bunter are away on an undercover assignment. During a practice air raid, a young woman is murdered in the village, and Superintendent Kirk recruits Harriet to help solve the murder, partly because the police are too busy organizing all the changes necessitated by the war and partly because as the wife of a detective, and as a crime novelist, she is the best qualified person to find the murderer. The murdered girl had come from the city as a "Land Girl", to do agricultural work and help the war effort. She was killed in the village street during an air raid drill, while most people were underground, and much of the investigation turns on the issue of who had been, or could have been, outside the shelter when the murder was committed. Many of the witnesses—and some of the possible suspects—are RAF pilots stationed at a nearby air base, who need to be questioned in between going out on missions. Gerald, Lord Peter's favourite nephew, who was first seen a decade earlier as a precocious boy playing a major role in solving "The Learned Adventure of the Dragon's Head" and appeared as an Oxford undergraduate in Gaudy Night; is now an RAF combat pilot. At least one character introduces the possibility that the murder is directly linked to German espionage. While conducting the investigation and riding herd on the five children under her charge, Harriet worried about her husband, whose life is in danger. She regrets the lost years when she had put him off before finally agreeing to marry him. Wimsey, realizing that the Germans had broken the code which he had been using, devises a new one which is unbreakable because of being based on things only he and Harriet knew. His Secret Service colleague brings her Peter's message and she shows considerable skill in decoding it. Eventually, Bunter comes back from the continent—uncharacteristically dirty, scruffy and so exhausted that he lets Lady Peter wait upon him and put him to bed—and is followed some days later by Peter, who arrived by a different route. It is never revealed where exactly they had been. Lord Peter is retired from active service and, while still involved in intelligence issues, would not be sent again behind enemy lines. Being presented with Harriet's record of her investigations—which, as he notes, already solved most of the mystery—he is able to add the last missing pieces. Finding the solution for the mystery does not mean, however, just handing the perpetrator to the police; rather, solving the mystery arouses a complicated new problem involving legal, military, ethical and moral issues—which Lord Peter manages to neatly tie up.