It is based on events around Operation Long Jump, the 1943 attempt by Nazi Germany to assassinate Winston Churchill, Joseph Stalin and Franklin Delano Roosevelt during the Tehran Conference.
Max Richard, an assassin of the Nazis, who was 37 years ago hired to assassinate Joseph Stalin, Winston Churchill and Franklin D. Roosevelt during the Tehran Conference, is holed up in today's Paris at the young French woman Françoise.
In flashbacks, he describes Françoise who claims to be a neighbor in his apartment because she mistook the door, the assassination attempts.
But Simon's interpreter Marie and the young Russian Secret agent Andrei get him on the loose.
The man who posed as a photographer and cinematographer "Dennis Pew" had a gun in his movie camera.
Andrei, who cares for the safety of the young woman, sends Marie, who is in love with him, to France.
At an auction of Max's documents in London, Andrej sees a young woman who is very similar to Marie.
Charles Aznavour's theme song "Une vie d'amour" became very popular in the Soviet Union which prompted the singer to record a Russian version titled Vechnaya lyubov (Eternal Love).