The year is 1973, and the tension of the Cold War is peaking. Amidst this, George Smiley, former senior official of Britain's Secret Intelligence Service (known as "the Circus" because its London office is at Cambridge Circus), is living unhappily in forced retirement, following the failure of an operation codenamed Testify in Czechoslovakia which ended in the capture and torture of agent Jim Prideaux. The failure resulted in the dismissal of Control, the head of the Circus, Smiley, and allies such as Connie Sachs and Gerald Westerby, and their replacement by a new guard consisting of Percy Alleline, Toby Esterhase, Bill Haydon, and Roy Bland. Since this, Control has died, Sachs has unhappily returned to civilian life, Westerby has returned to journalism, and Smiley's former protege, Peter Guillam, has been demoted to lead the scalphunters, a posting designed to be insulting due to the dirty work the department does in comparison to the significance of his former rank.