Jacques Tourneur - Out of the Past (1947)

Out of the Past is so perfect a film noir that it is considered practically a textbook example of the genre. In his first starring role (it had previously been offered to John Garfield and Dick Powell), Robert Mitchum plays Jeff Bailey, the friendly but secretive proprietor of a mountain-village gas station. As Jeff's worshipful deaf-mute attendant (Dick Moore) looks on in curious fascination, an unsavory character named Joe (Paul Valentine) pulls up to the station, obviously looking for the owner.
Jeff is all too aware of Joe's identity; he's been dreading this moment for quite some time, knowing full well that it will mean the end of his semi-idyllic existence, not to mention his engagement to local girl Ann (Virginia Huston). In a lengthy flashback, the audience is apprised of the reasons behind Jeff's discomfort. Several years earlier, he'd been a private detective, hired by gangster Whit Sterling (Kirk Douglas) to find his mistress Kathie Moffett (Jane Greer), who shot him and ran off with $40,000. Jeff traces Kathie to Mexico, but when he meets her he falls in love and willingly becomes involved in an increasingly complicated web of double-crosses, blackmail, and murder.