 Chicago cabinetmaker John Colter is abducted at gunpoint and repeatedly beaten by a would-be thief who mistakes him for diamond merchant Harry Barlowe. Colter s worried wife Martha notifies the Highway Patrol, but there are few leads until Dan Mathews spots Barlowe (who has a very similar car and license plate) checking in at the Pinewood Motel. When Dan learns that Barlowe is carrying diamonds, he deduces that a thief working with Barlowe s partner Al Dixon is responsible for Colter s disappearance. Dan knows that the injured Colter will be very difficult to find unless the thief can be caught, so he enlists the aid of an attractive female deputy sheriff to set a trap that will lure him into the open.