It's 1965, and the Cold War has never been colder. The Circus—the secret center of British intelligence—has one prize asset left in Moscow: a senior Red Army officer with access to the enemy’s deepest secrets. But when a British agent is shot in Helsinki, George Smiley uncovers a Soviet operation that imperils this irreplaceable source.

The trail leads Smiley not to Berlin or Vienna, but Los Angeles—the most foreign please he has ever known. There, in the murky heart of US intelligence, a Communist sleeper agent—a “Taper Man”—is poised to expose Britain’s operative in Moscow. To save him, Smiley must navigate an America convulsed over its identity and freedoms, all while his spy in Leningrad, Roy Bland, risks everything in pursuit of a Russian defector who holds the final piece of the puzzle.