In 1920 in Mumford, Sir John Middleton’s cook, Mrs. Gravely, found the old family dog dead at 2 o’clock before going back into the house to find her boss dead, as well. This sequence of events bothered Rutledge, a detective investigating the death of Sir John. The local constabulary had brought in a suspect and Rutledge talks with the local doctor who tells him the cause of death was a blow to the back of the head. 

Rutledge interviews Gravely who tells him that in Sir John’s dying breaths he uttered a single word: “Trafalgar.” She also said that he was still barely alive by the time the doctor reached the house and that he spoke with the doctor, although she couldn’t hear what they said to one another. The doctor told Gravely to go outside and wait for the ambulance but in 5 minutes came out and told her instead to get a hearse. Rutledge then asked the cook to identify pictures of Sir John’s family.

Next, Rutledge speaks with Sam Hubbard, a farm worker who worked for Sir John and buried his dog after he died. Hubbard also worked for Sir John during the war and said he would have laid down his life for the man. The detective also talks with the rector, Mr. Harris, who describes Sir John as a lonely man who had traveled from Hereford after the war ended and his wife died of Cholera in India. Harris remarks how odd it was that the dog was found dead outside, as Sir John would have never opened the door for him to go outside at his age.

Rutledge determines that the killer must have been someone Sir John knew, as the murder happened deep inside the house and he must have opened the door and invited someone in who then struck him from behind. In the study, the detective looks through the old general’s records of his two wives’ deaths. In the room, he also comes across a manuscript about the war Sir John had been working on and wonders if he had been killed before he could finish an incriminating paragraph. He also discovers a painting of a house with a caption that read “Trafalgar, Dartmouth, Devon.” Trafalgar refers to the family house in Dartmouth which Sir John had recently inherited, passing over the next in line who had been disinherited by the family. 

Mrs. Gravely told Rutledge that Sir John’s most recent visitor had come before Christmas. The man had carried a cane, scared the dog, and refused to identify himself, telling her to tell Sir John he was an old comrade in arms. Rutledge tells the constable he is driving up to Dartmouth to find the house called Trafalgar. He speaks with a man called Hillier who tells him the house isn’t called that anymore and was abandoned after the last owners left. He hires a man to sail him across the river to the house and finds tracks in the abandoned house from a recent inhabitant. Rutledge discovers that Sir John left the house to Mrs. Gravely to inherit after the person who was next in line had supposedly died years ago. 

Next, the detective interviews Sir John’s nephew, Dr. Barnes, who he identifies as the person who left the tracks in the Trafalgar house. The nephew says he did not want the house and has not seen his uncle in a while. Rutledge revisits the nephew after further investigation and he admits that he murdered his uncle and the dog had been put outside after it bit him when he entered. After the nephew’s wife was diagnosed with colon cancer, he asked his uncle for money but was denied. When his uncle asked him to cure his dying dog after he’d refused to save his wife, the nephew killed him. Rutledge turns the man into jail and determines the murder weapon to be a metal doorstop used to prop open the door for the dog to go in and out.