The Great Sinner 1949. Gregory Peck, Ava Gardner, Melvyn Douglas, Ethel Barrymore, Walter Huston, Agnes Moorehead
When accomplished novelist Fedja (Gregory Peck) becomes enamored of the stunningly beautiful and mysterious Pauline (Ava Gardner) on a train to Paris, he abandons his plans and instead goes with her to a German casino. Fascinated by the people he meets there and wanting to remain near Pauline, he decides to study the gamblers as research for his next book. Pauline, however, is a consummate gambler herself, and her addiction slowly pulls Fedja into a world of corruption and lost luck.