A young French historian, Napoleon Beranger, comes to Warsaw on a foreign scholarship. While driving his car along a detour he runs into an old manor in Walewice village. On the wall of the manor he finds portraits of Napoleon Bonaparte and his great love Maria Walewska, a Polish aristocrat who used her charms to convince the emperor to stand up for her country. Beranger meets there by accident a beautiful woman, a student of art history by the same name of Maria Walewska (Marysia). The pair of modern heroes both notice the striking resemblance of each other to the historical figures, and as if by magic, move back into the Napoleonic period, where they play the roles of Napoleon and his Polish consort. They fall in love.