Commander Adam Dalgliesh is asked by a friend, Home Office Minister Sir Paul Berowne, to be aware correspondence of a personal nature he's received. He's not being blackmailed and so there's nothing to investigate per se and he only wants Adam to keep an eye on what's going on. Sir Paul's personal life is somewhat complicated. He lives in the shadow of his late brother Hugo and has little time for his wife Barbara who is having an affair with Stephen Lampart. She is now pregnant but insists that the child is his. He's fed up with it all and decides to chuck it all in....

Sir Paul Berowne gives his latest anonymous letter to Adam Dalgliesh and the next day visits Father Francis Barnes at St. Matthews Church in Paddington, requesting permission to spend one night alone in a spare room at his church. The next day, Sir Paul's body is found by Mrs. Wharton, a church volunteer, his throat slit. There was also a homeless man, Harry Mack, also dead in the room with him. Dalgliesh takes charge of the case and learns from Father Francis that he had only known Berowne for less than two weeks but had noticed something very peculiar at communion. ...

Commander Dalgliesh and Insp. Miskin continue their interviews with those associated with the case. Gordon Halliwell, the family chauffeur, came to the Berowne family after serving with the deceased Hugo in the army. He freely admits that he and Sir Paul didn't along. Barbara Berowne's brother Dominic Swayne has an alibi. Dalgliesh also questions him about the death of the Berowne family's servant, Diana Travers, who drowned. Swayne says she wasn't an unemployed actress as she claimed. Berowne's daughter Sarah didn't get on with her father and were estranged owing to ...

Berowne's daughter clearly has a secret that she has not shared with anyone except Ivor Garrett. Dalgliesh re-interviews Lady Berowne, Sir Paul's mother, and she lets it slip that he had a mistress. She is Carole Washburn who tells Dagliesh that Berowne had gone through a religious conversion. She refuses however to disclose anything else about their relationship other than they met at work and were always discreet. Dalgliesh visits the site where Diana Travers drowned and learns from the restaurant doorman, Henry, that Berowne was there the day of the drowning and ...

Millicent Gentle tells Dagliesh of the day Diana Travers died. Annoyed by the revelers on the water she had gone out and saw Sir Paul Berowne fighting with another man. He was soaking wet and she invited him back to her cottage to dry off. Berowne admitted the fight was about a woman and they spent about two hours talking. She also saw him on the day of his death when he came to visit but he had little to say and left quietly. Dalgliesh quickly determines that Berowne had fought with his brother-in-law Dominic Swayne who denies killing him. Dalgliesh is upset to learn...

Dalgliesh visits the church where Berowne was killed and is surprised when Father Francis finds a button in the offerings box. Emily Wharton thinks it must have been young Darren who put it there instead of the 10 pence she had given him to go and light a candle. The Berowne's cook, Miss Matlock, clearly recognizes the button but says she can't recall where she's seen it. Halliwell the chauffeur tells Dagliesh that he drove Sir Paul's mother to the church on the evening her son was killed.