At the center of John le Carre's Tinker, Tailor, Soldier, Spy (both thematically, and structurally), there is a show-down of sorts between Smiley and Karla. What is the nature of that show-down? In other words, what is at stake for each of them?
John le Carre's [real name: David John Moore Cornwell] Tinker, Tailor, Soldier, Spy is loosely based on the author's actual experiences working for the British intelligence services. The story reflects the nature of the Cold War, and competition between the intelligence services of Britain and Soviet Russia to discover useful intelligence about their opponents while concealing their own military secrets.
The feud between Soviet and British intelligence is evoked in the novel as a cat and mouse game between the British intelligence agent, George Smiley, the protagonist of the novel, and a Soviet agent code-named Karla. These two characters recur in two subsequent novels, The Honourable Schoolboy and Smiley's People. The Karla arc is only completed when Karla's need to get western medical help for his daughter enables him to be captured in Smiley's People.
Although there are reported encounters with Karla, including a memory of their one personal encounter in the past, Smiley does not actually meet Karla in the course of the novel. The show-down is indirect, with each trying to reveal the others' moles and keep their own secret. In this subtle and indirect confrontation, we discover that Haydon is Karla's agent, and that one of the things that Haydon has done at Karla's behest is had an affair with Smiley's wife. Thus what was at stake for Karla was his professional stature but for Smiley his marriage as well as his job was at risk.