Gumshoe Philip Marlowe (Dick Powell) is hired by the oafish Moose Malloy (Mike Mazurki) to track down his former girlfriend. He's also hired to accompany an effeminate playboy buy back some jewels. When the exchange results in the playboy's murder, Marlowe can't leave the case alone, and soon discovers it's related to Malloy's. As he gets drawn deeper into a complex web of intrigue by a mysterious blonde (Claire Trevor), the detective finds his own life in increasing jeopardy.