Michael Redgrave is on the train to his job as a crane operator. He sees at a window Paul Lukas killing Sally Gray.
It's a great start for a movie, and it was used before. LADY IN DISTRESS is a remake of the French METROPOLITAIN. I'd like to offer you a comparison of the two movies, but I've never seen the earlier film. I do know that Michael Redgrave is miscast as a working stiff who rides around in taxicabs. Sally Gray, on the other hand, impresses me as more than eye candy with a sullen expression for the first time. She's very good as the unwilling femme fatale who drives her husband, stage magician Lukas, crazy with jealousy, talent manager Hartley Power, sad with hopelessness and Redgrave mad with the possibilities of a magical night.
There are many early noir elements in this movie, filled, as it is, with Gallic fatalism, and can be viewed as an important step in its evolution. It's just not a film noir in itself.