Alec Leamas is a spy for the British secret service (also known as the Circus), who is stationed in West Berlin in the early 1960s. His life as a spy is based on constant deception and manipulation, which causes Leamas to become cynical and worn out. However, when the Circus wants him to get rid of Mundt, the sadistic head of the Abteilung (East German intelligence) responsible for killing several of the agents under Leamas's command, Leamas takes the assignment of impersonating a bitter defector. But when Leamas and Liz Gold, an idealistic communist, fall in love, he sees a chance to salvage and rebuild his life away from the manipulations of Cold War espionage. However, the tension grows between his work as a spy and his desire for a normal life with Liz. He tries to protect her from being drawn into his work, but Leamas cannot simply stop being a secret service operative. He struggles throughout the novel on the borderline between the world of love and the world of cold-blooded political pragmatism represented by the Circus and by the Abteilung. Leamas clearly sees the negative aspects of the work he does and understands what it has cost him, but is still capable of defending it as necessary for the greater good. His challenge becomes how to live outside it, or if that is even possible.
Liz Gold is a Jew. However, Liz, like other Jewish characters, is nonreligious or practicing. Nonetheless, even years after the Nazi period has ended, the old vestigial categories still have strength to injure and affect outcomes. She is an idealistic communist who believes the Communist Party will bring peace and prosperity to humankind. Liz has a strong sense of integrity: she says what she means and is uncomfortable with deception. When Liz meets Alec Leamas, she soon falls in love with him. Although Liz doesn't agree with Leamas's cynicism about life, under his bitter façade she finds him to be a caring person. When Leamas says he has to leave permanently, she accepts this, but is brokenhearted. Liz's strengths, namely her purity and her loving nature, are considered weaknesses by the Circus and Abteilung, who exploit Liz. When Liz discovers she is being manipulated to provide evidence at a trial that might harm Leamas, she is morally outraged. She points out that the Circus is hypocritically protecting Mundt, a sadistic former Nazi. Eventually, Liz is shot to death when she and Leamas attempt to cross over the Berlin Wall. In this way, she becomes another victim of the Cold War.
Fiedler is a nonpracticing Jew, a lawyer, and second in command to Mundt in the Abteilung. Like Liz Gold, Fiedler has integrity. He really believes in the ideals of the Communist Party and in being honest. For example, he tells Leamas the truth instead of leading him on. However, Fiedler is not innocent like Liz. He fully understands the manipulation and treachery involved in Cold War espionage and politics. Fiedler's hatred of Mundt is understandable because Mundt is a sadistic former Nazi, who hates Fiedler because he is a Jew. Fiedler forms a friendship with Leamas—they are two enemies who respect each other. As Fiedler talks with Leamas, he realizes that the Circus and the Abteilung in some ways are very similar. Both organizations believe that the end justifies the means and that individuals should be sacrificed for the good of the whole. When Fiedler discovers he has been caught in a trap created by the Circus, he seems resigned to being another casualty of the Cold War. Also, he understands that he and Liz have been exploited because they are from Jewish background and thus outsiders in both British and East German society.