George Smiley has retired after the events of Call for the Dead. He is asked to look into the murder of the wife of a teacher at the exclusive Carne public school, as he can mix socially with the staff while the police cannot. She had sent a letter predicting that her husband would murder her. The couple were from a lower-class, Nonconformist background. He had tried to assimilate, she had not, and it had rankled the snobs.
Smiley finds class prejudice and moral ambiguity as he observes and questions. Some classic le Carré stylistic tics are already present: The over-the-top, aristocratic Fielding is a precursor to Jerry Westerby and Larry Pettifer.