About one of the operations of the Soviet counterintelligence "Smersh", which began in 1944 and ended in 1947. It was a deadly confrontation between the Soviet counterintelligence and Western intelligence services, which continued after the defeat of Nazi Germany. The focus of the film is: the feat of our intelligence officer, who remained secret for a long time, risking his life daily and hourly, working in conditions where failure and betrayal are ordinary events, continuing his mission even after being accused of treason. Four episodes of the film "A Legend for a Traitor" cover the main events of four years of desperate struggle, full of heroism and betrayal, despair and hope, hatred and love.