Part one of the film shows the establishment of the first organized police dog unit in Baltimore, Md., in 1957; the step-by-step training of a police dog named Duke from the time the dog is accepted by the Baltimore Police Department to the day when he saves the life of his master; and a narcotics dog's successful shipboard search for a kilo of hashish. In the second part of the film, dogs from the Washington, D.C., K-9 Corps are shown searching for bombs in the Robert F. Kennedy Stadium and at Dulles Airport and entertaining crowds at training demonstrations. Police dogs in Minneapolis, Minn., are seen searching for a lost child in a park, helping an officer apprehend two criminals, and locating evidence that leads to the arrest of a man who attacked nine women. In San Francisco, an officer and his dog are shown conducting a successful building search for a burglar. Another officer tells how he was able to arrest 13 people with the aid of his police dog. The film emphasizes that in all of the cities shown, the K-9 Corps have proved an important deterrent to crime.