A Legacy of Spies is both a prequel and sequel to John le Carré's The Spy Who Came In from the Cold. In that book, MI6 agent Alec Leamas, motivated by the death of his operative Karl Riemeck in East Berlin, agrees to undertake one final mission to get revenge on the man he believes to be Riemeck's murderer, a high-ranking member of the Stasi named Hans-Dieter Mundt.
In the course of Leamas's mission, which finds him unexpectedly extracted to East Berlin, he – along with his lover, a young Communist sympathiser named Liz Gold – is shot to death at the Berlin Wall, on orders of Mundt. The men responsible for dispatching Leamas – intelligence chief Control, Control's right-hand-man George Smiley, and Smiley's protégé Peter Guillam – escape unscathed, and it is revealed that Mundt was a double agent they were trying to protect all along, without telling Leamas.
