Set in 1965 in the midst of the Cold War, follows a French scientist, Francis Mareuil, as he begins working as a spy. While working for the French Secret Service and the CIA, Mareuil meets Lyudmila Goloubeva, a pianist forced to work for the KGB. A romance blossoms between them but neither can be sure what is an expression of their true feelings, and what is the fruit of political shenanigans…