Plot
David Cummins (Kent Smith) is trapped in a dry cistern and wondering whether he will die there. The largest portion of the rest of the film is a flashback to a week earlier then forward, detailing the events that landed him in that precarious pit.
David, a bright but down-and-out vagrant, is tapped by a police officer for looking longingly in a pawn shop window at a revolver. A smart retort to the officer's question has him carted off to jail for "no visible means of support." The following day he is in court hearing "$50 or 30 days."
Listening to the exchange is cagey lawyer Philip Cagle (Robert Douglas), who pays his fine. After a meal and a taxi ride the pair enter the attorney's office, where he explains why. The counselor is the executor of the estate of a wealthy man, Malcolm Taylor, whom the bum just happens to resemble exactly. The rich man has been missing for seven years minus two weeks and is about to be declared legally dead, which would be inconvenient for the lawyer (though it is unclear why).
If David will agree to impersonate the missing man he will be paid $500. David holds out for $5,000 and the pair come to terms, then drive to the missing man's huge house near a cliff. During the journey the lawyer adds some information about the man's task. He must fool three people — the man's wife, his brother and the brother's wife. He adds at the end of the trip, just as they arrive: "By the way, your brother hates you."
David soon finds that it is not just the brother, Calder (John Alva), who is none too fond of him. His wife Evelyn (Viveca Lindfors) is more than a little estranged, apparently as a result of the husband's many affairs and general callousness before his disappearance. Fortunately, Evelyn doesn't know that her husband Malcolm's most recent affair was with Calder's wife, Nadine (Janis Paige).
When David reaches the estate, the owner's dog, Angel, bares his teeth. David lets the dog smell the owner's jacket sleeve (it is not explained how David got this jacket which must be at least seven years old) and the dog backs off. The impersonation comes off well for some time as David insinuates himself into the family, becoming increasingly fond of his supposed wife Evelyn. But Nadine becomes suspicious when she notices his hands, which lack some tell-tale scars. David tells Philip and the lawyer connives to have her meet him at a lonely spot on the estate, then shoves her off the cliff.
The police declare Nadine's death to be an accident. David decides to leave and Philip offers him a ride, but knocks him out when they are alone and tosses him into the cistern. When David regains consciousness, he discovers the skeletal remains of Malcolm Taylor next to him. Eventually he figures out how to climb out of the cistern – a slow, arduous process.
Meanwhile, Philip points out to the grieving Calder how unlikely it was that Nadine's death was accidental, and reminds him that Evelyn and Nadine hadn't gotten along. Calder, now convinced that Evelyn killed Nadine, escorts her to the cliff, accuses her of murder, and tries to push her off. As they struggle, David, who has just reached the top of the cistern, hears Evelyn's screams and rushes to rescue her just in time.
David and Evelyn confront Philip. As he flees, the dog Angel chases him and catches him next to the cistern, the lid still open from David's escape. Philip falls into the cistern while fighting off the dog.
All is confessed to the puzzled police and all is resolved, with Evelyn unwilling to press charges against David and showing that she now returns his feelings.
