After a gang of thieves fail in a bank robbery attempt, they decide to have their work done for them by trained Dobermans. They hired a dog trainer on the pretense of wanting the dogs to do security work. The dogs pull off their robbery successfully, but when they return to the hideout, they prevent their exploiters from getting to the money and then run away.

After Jojo, one of three bank robbers, mistakenly tosses the cash he has just stolen into the trunk of the wrong car, the thieves are forced to flee to their motel empty-handed. In analyzing what went wrong, Eddie Newton, the gang's smooth-talking leader, concludes that his carefully devised plan was disrupted by the unpredictable "human factor." Later, Eddie sees three young men who have broken into a used car lot being chased and cornered by vicious guard dogs. Impressed by the animals' quickness and tenacity, Eddie inquires about them at a pet store and learns they are Doberman pinschers. Hitting on a plan, Eddie poses as a magazine writer and seeks out Barney Greer, a young Air Force officer and Vietnam veteran who trains dogs for combat duty. While pretending to interview him, Eddie tells Barney that he wants to start a dog security business and persuades him to become his partner once he has been discharged. Eddie then scopes out a small-town bank and, using a camera hidden in a fake arm cast, takes photographs of its interior. Nearby, Eddie also finds a rundown, secluded ranch to rent and, with help from lover June, a former waitress, Jojo and fellow crook Sammy, fixes up the place. When the newly discharged Barney arrives at the ranch, he approves of the facilities but balks when Eddie informs him that he will be training Dobermans. After Eddie convinces Barney, who previously had trained German shepherds, that he can work with Dobermans, Jojo and Sammy show up with six Dobermans and a bulldog named after FBI director J. Edgar Hoover. Barney begins training the Dobermans¿Bonnie, Clyde, Ma Barker, Dillinger, Pretty Boy Floyd and Baby Face Nelson¿but soon discovers that while they are quick learners, they do not always stay on task and can turn on their trainers. Although Eddie tries to reassure him, Barney grows suspicious and questions June about the true nature of the operation. June is evasive, but in the ranch's barn, Barney finds giant blow-ups of the bank photographs taken by Eddie and deduces that the others are planning to use the dogs in a robbery. When Barney, whose life was once saved by a dog, confronts Eddie and announces he is leaving, Eddie laments that he will now have to kill the dogs. June encourages Barney to continue, and Barney reluctantly agrees. With Barney on board, Eddie reveals the details of his $600,000 heist and the fact that only the dogs will be in the bank during the hold-up. To assure that the animals complete their assigned tasks, Barney trains each dog to respond to the sound of a specific high-pitched whistle, audible only to dogs. Eddie, meanwhile, stakes out an office in an unoccupied building across from the bank, from which he and Barney can direct the robbery. Eddie then tells June that she will not be getting an equal share of the loot, but will receive a much smaller amount from him. Although June appears to accept the arrangement, she flirts with Barney and suggests they go into business together after the robbery. Soon after, June fights with a jealous Eddie, and he hits her in front of the others. Despite the discord, the gang proceeds with the heist, but the robbery is aborted when drapes in the bank's front windows are closed unexpectedly, obscuring the thieves' view from the office building. Posing as an office cleaner, Eddie removes the drapes and resumes the heist. While watching from the office window with Eddie and June, Barney begins blowing the whistles, signaling the dogs to undertake each task in turn. The dogs, who are wearing nail-studded collars as protection against being choked, execute their jobs perfectly, attacking and disarming the bank guard and surrounding everyone else. At that point, Barney, having learned that Eddie still intends to kill the dogs, leaves in protest, but June volunteers to finish the job and blows the whistle that directs Dillinger to deliver the robbery note to a bank teller. After the teller reads the note aloud, the bank manager tries to place phony bills into the bags that are strapped to the dogs's backs, but the Dobermans growl threateningly until real cash is deposited. Following a trail of ranch dirt that has been scattered by Jojo and Sammy, the dogs then race toward home. Along the way, Bonnie is hit by a car, but Dillinger picks up her bags with his teeth and continues to the ranch. When the surviving dogs arrive, June blows the whistles, commanding them to attack and disable Jojo, Sammy and Eddie. June then directs the dogs toward her waiting car, but before she can get the cash from them, J. Edgar grabs the pack of whistles and runs off. The Dobermans chase J. Edgar across an open meadow, quickly leaving the pursuing June behind.