The Big Sleep (1946)

Private Detective Philip Marlowe (Humphrey Bogart) is hired to investigate Carmen Sternwood (Martha Vickers) and the debts she owes to a shady bookseller. Her older sister Vivian (Lauren Bacall) becomes involved and tries to tell the shamus how to do his job. Several murders later, the complex narrative takes a new turn when Vivian receives a blackmail note that includes scandalous pictures of her sister. The storytelling is compelling, as is the chemistry between Bogie and Bacall.