"Scarlet Street" is a 1945 film noir directed by Fritz Lang, based on the novel "La Chienne" by Georges de La Fouchardière. The story follows Christopher Cross, a lonely and middle-aged cashier who becomes entangled in a web of deceit and betrayal after he helps a young woman named Kitty March. As Cross becomes infatuated with Kitty, he is manipulated by her and her boyfriend, leading to tragic consequences. The film explores themes of obsession, morality, and the darker aspects of human nature, showcasing Lang's signature style and the complexities of its characters.