In November 1973, "
Control", head of
British intelligence ("The Circus"), sends field agent
Jim Prideaux to
Budapest to meet a
Hungarian general and potential defector, who has offered to identify a
mole installed by
Soviet spymaster
Karla amongst the Circus' senior leadership. Prideaux realises the meeting is a trap, attempts to leave and is shot in the back. Control and his deputy,
George Smiley, are forced to retire, and Control dies shortly after. Sir Percy Alleline becomes the new Chief,
Bill Haydon his deputy, and Roy Bland and
Toby Esterhase his lieutenants. Despite Control's and Smiley's suspicions, the four had begun handling a high-level Soviet source ("Operation Witchcraft"); Alleline later begins sharing Witchcraft intelligence with the Americans. Alleline and Bland meet with
Permanent Undersecretary Oliver Lacon, the senior civil servant responsible for the Circus, to discuss the ongoing cost of a secret
safe house to meet the Witchcraft source. After the meeting, field agent
Ricki Tarr, currently in hiding due to being connected to several deaths in Istanbul, telephones Lacon to inform him of a mole within the Circus. Aware that Control had a similar theory, Lacon asks Smiley to investigate. Smiley recruits
Peter Guillam and retired
Special Branch Inspector Mendel to assist him. After setting up a base in the Hotel Islay, Smiley has Guillam steal personnel records and copies of the Circus'
slush fund accounts. He discovers several Control loyalists were ousted after Prideaux's shooting, as well as a record of payment made to "Mr. Ellis", one of Prideaux's identities,
after the shooting. In Oxford, Smiley interviews analyst
Connie Sachs. Sachs had discovered evidence that Soviet
cultural attaché Alexei Polyakov was actually a military officer, and suspected his true role was
to run a mole in London; Alleline had scoffed at her findings and sacked her. Back in London, Smiley discovers Tarr in his house. Tarr tells how he was assigned to trail Boris, a Soviet trade delegate in
Istanbul who was offering to defect, but who he quickly guessed was actually
KGB. After Tarr witnessed Boris assault his wife and fellow agent Irina, he and Irina began an affair. Irina offered to reveal the identity of a top-level mole in exchange for asylum in the West. Hours after Tarr cabled London about the existence of a double agent, the local
station chief was murdered and Irina abducted. Smiley sends Guillam to the Circus archive to steal the duty officer's logbook for the month Tarr contacted London. Guillam, who had been Tarr's boss, is unexpectedly brought before Circus leadership and told that Tarr, who has been detected in Paris, is a traitor who has been bribed by the Soviets. Guillam returns to Smiley's house and, discovering for the first time that Tarr is there, punches him, but Smiley finds that the logbook pages for the relevant night have been removed, supporting Tarr's story. That night, Smiley recounts his only meeting with Karla to Guillam. While working under the name "Gerstmann" in 1955, Karla was captured and traded to the Soviet Union by the Americans. Believing he would likely be executed upon his return, Smiley travelled to
Delhi to recruit him. However, his constant urging for Karla to think of his wife only revealed Smiley's weakness: his love for his wife, Ann. A
chainsmoker, Karla listened silently, stole a
lighter given to George by Ann, and returned to the Soviet Union. Smiley contacts another sacked loyalist, former
duty officer Jerry Westerby, who tells him of how Prideaux's shooting sent Control into shock. Hoping to find George, Westerby had telephoned Ann; Haydon then arrived and took charge. Guillam wonders how Haydon could have learned of the emergency, to which Smiley informs him that Haydon was having an affair with Ann. Smiley interviews Prideaux, who is working as a French teacher at a
prep school. Prideaux explains that his Budapest mission was to identify the mole and relay one of five code-names to Control drawn from the English children's rhyme "
Tinker, Tailor". Alleline was "Tinker", Haydon "Tailor", Bland "Soldier", Esterhase "Poorman", and Smiley "Beggarman". However, he was captured and tortured by the KGB, during which he witnessed Irina's execution. During his interrogation, Karla personally visited and asked how close Control was to identifying the mole before trading Prideaux back to the Circus. Smiley realises that Witchcraft is actually a KGB ruse. The four Witchcraft lead officers believe Polyakov is trading sensitive Soviet military and political intelligence for trivial British material. In reality, Polyakov is trading false or insignificant intelligence and the mole is using the arrangement to leak substantive British intelligence. Smiley informs Lacon and the Minister that the true object of Witchcraft is to lure the
CIA into sharing US intelligence, which the mole can then leak to Karla. To draw out the mole, Smiley and Guillam send Tarr to the Paris Station to cable the Circus. To ensure his compliance, Smiley agrees to Tarr's request to trade the mole for Irina, despite knowing she is dead. Smiley and Guillam surprise Esterhase as he leaves the Circus and drive him to an airstrip where they threaten to deport him until he provides the address of the safe house. Smiley and Guillam wait at the safe house for the mole to alert Polyakov that Tarr is about to blow their cover. The mole is revealed to be Haydon, and Smiley arrests him at gunpoint. The Circus holds Haydon at its training and debriefing facility,
Sarratt. Smiley informs him he will be
traded for British operatives held in the Soviet Union, and agrees to settle several of Haydon's sexual relationships with both women and men. Haydon informs him that Karla ordered him to seduce Ann to cloud Smiley's judgment. He also confirms that Prideaux, a long-time friend (and, it is hinted, lover), suspected Haydon was the mole and tipped him off before his Hungary mission. Haydon was able to inform Karla and prevent Prideaux from being killed by the KGB. Prideaux, however, blames Haydon for allowing his torture. Prideaux infiltrates Sarratt with a hunting rifle and kills Haydon from a distance, shooting him in the cheek and watching as he collapses. Ann returns home, and Smiley returns to the Circus as its chief. ==Cast ==