After an engagement of some months following the events at the end of Gaudy Night , Lord Peter Wimsey and Harriet Vane marry. They plan to spend their honeymoon at Talboys, an old farmhouse in Harriet's native Hertfordshire which Wimsey has bought for her, and they abscond from the wedding reception, evading the assembled reporters.
Arriving late at night, they are surprised to find the house locked up and not prepared for them. They gain access and spend their wedding night there, but next morning they discover the former owner, Noakes, dead in the cellar with head injuries. The quiet honeymoon is ruined as a murder investigation begins and the house fills with policemen, reporters, and brokers' men distraining Noakes' hideous furniture.
Noakes was an unpopular man, a miser and (it turns out) blackmailer. He was assumed to be well off, but it transpires that he was bankrupt, owed large amounts of money, and was planning to flee his creditors with the cash paid for Talboys. The house had been locked and bolted when the newly-weds arrived, and medical evidence seems to rule out an accident, so it seems he was attacked in the house and died later, having somehow locked up after his attacker. The suspects include Noakes' niece Aggie; Mrs Ruddle, his neighbour and cleaning lady; Frank Crutchley, a local garage mechanic who also tended Noakes' garden; and the local police constable, who was his blackmail victim.
Peter's and Harriet's relationship, always complex and painfully negotiated, is resolved during the process of catching the murderer and bringing him to justice. In a final scene, in which almost the entire cast of characters is gathered in the front room of Talboys, reflecting the novel's origin as a work for the stage, the killer turns out to be Crutchley. He planned to marry Noakes' somewhat elderly niece and get his hands on the money he had left her in his will. He set a booby trap with a weighted plant pot on a chain, which was triggered by the victim opening the radio cabinet after locking up for the night. Wimsey's reaction to the case– his arrangement for the defendant to be represented by top defence counsel; his guilt at condemning a man to be hanged; the return of his shell-shock – dominate the final chapters of the book. It is mentioned that Wimsey had previously also suffered similar pangs of conscience when other murderers had been sent to the gallows. His deep remorse and guilt at having caused Crutchley to be executed leave doubt as to whether he would undertake further murder investigations – and in fact Sayers wrote no further Wimsey novels after this one.
The 1942 short story Talboys , the very last Wimsey fiction produced by Sayers, is both a sequel to the present book, in having the same location and some of the same village characters, and an antithesis in being lighthearted and having no crime worse than the theft of some peaches from a neighbour's garden.