| Director | Burt Brinckerhoff |
|---|
Harlan Thompson (David McCallum) is the head of the biology department at Southwestern University, a small school located in an isolated southern California town. Though he dresses casually and socializes with the students, he is frequently at odds with his fellow professors and the administrators, viewing them as shallow, elitist snobs who are more interested in status than education. However, he takes a semi-liking to a young and newly hired biology professor, Michael Fitzgerald (George Wyner), and tries to stop him from being sucked into the system. The only other SU employee whom Harlan seems to have any use for is his ex-girlfriend Caroline Donaghue (Sandra McCabe). The two have recently broken up, but remain on good terms.
Recently, several cows belonging to local rancher Larry Ludecky (Larry Gene Darnell) have been found dead. Harlan suspects that they have been killed by coyotes, but rules that out upon examining the cows. Larry says that he is going to wait with a rifle and shoot the animals who have been killing his cows if they return. Disregarding a warning from Harlan, Larry goes ahead with his plan and is killed by a pack of dogs. Shortly afterward, dogs also kill an SU student and an elderly lady.
Harlan and Michael discuss the evidence and conclude that the killings were committed by dogs, who have formed packs via Michael's theory that pheromones cause animals of a particular species to unite and act as one. The pheromones may be coming from a top-secret government experiment being conducted at a linear accelerator near the school. Harlan and Michael share their conclusion with the SU president, Dr. Martin Koppelman (Sterling Swanson), and ask him to warn people to keep their dogs home at night. Koppelman, believing that Harlan and Michael are wrong, declines their request. Harlan says he will give them a warning himself, and Koppelman threatens him with firing if he does.
However, at the same time, a local kindergarten class is having a dog show, at which the dogs pack and attack the people. While no one is seriously injured, the town now becomes aware of the dog packs. Several men form a posse to hunt the dogs. Sheriff Jimmy Goodman (Eric Server) discourages them, but they insist, and he ends up joining them.
Harlan and Michael attempt to perform a pheromone experiment on a dog inside a plastic encasement. If it works, they plan to have a stronger pheromone sprayed into the area to stop the packs. But as they are about to start the experiment, the dog breaks through the plastic amid a nearby pack. Meanwhile, the posse is attacked by a pack, killing everyone but Jimmy, who flees the scene. But before he gets to his car, he is attacked also, dropping his gun. After suffering severe injuries, he stops the attack by picking up his gun and shooting the dog, but collapses and dies upon reaching his car.
Meanwhile, SU professor Dr. Charles Aintry (Dean Santoro), brings fellow professor Charlotte Ingle (Linda Gray) home from a date. He asks to go inside, but she declines, and he expresses suspicion that she does not want to see him anymore. She implies that she is not romantically interested in him and goes inside, while he leaves, feeling dejected. Then, while taking a shower, she is killed by a dog.
Harlan and Michael arrive at the police station and find a man dead. They call Jimmy on the radio. Getting no response, they each grab a rifle and leave. As they pass Koppelman's house, they see him being attacked by a dog. Seeing Harlan and Michael, Koppelman asks them to shoot the dog. Michael shoots, but accidentally shoots and kills Koppelman. Harlan then shoots and kills the dog. Michael is traumatized upon realizing that he killed Koppelman, but Harlan calms Michael down. The two then find Mrs. Koppelman (Holly Harris) dead in the swimming pool.
Michael says that he will warn the students and tells Harlan to check on Caroline, and that Harlan and Michael will later meet at the dorm. Harlan tells Michael to take Koppelman's car, which he does.
Harlan arrives at Caroline's house and tells her that they need to evacuate. A few seconds later, as the howling of dogs is heard in the far distance, her dog begins trembling.
Back at SU, Michael gathers the students in the lobby of the dorm. He tells them about the dog attacks, that he will walk them over to the library in five minutes, and that the campus will be evacuated in the morning. The students do not take Michael seriously, but grudgingly agree to his orders. One of the students named Cory tells Michael that Cory's roommate, the overweight Howard Kaplan (Barry Greenberg), was hungry and went to the cafeteria. There, Howard finds milk and rolls, but is quickly confronted by some barking dogs. Michael arrives and tells the panicked Howard to throw the food to the dogs, which he does. Two of the dogs goes after the food and Michael attempts to shoot the other. He turns out to be out of bullets, but he disables the dog by striking it with the rifle. He and Howard leave and head for the dorm.
Back at the dorm, the students, having concluded that Michael has forgotten about them, walk to the library themselves.
Back at Caroline's house, as Caroline goes to get dressed, she screams. A dog walks into the living room, and is quickly shot and killed by Harlan. However, several more dogs enter within a few seconds. Harlan and Caroline, holding her dog, exit the house.
Michael and Howard arrive back at the dorm, finding it abandoned. Meanwhile, the other students are attacked by a pack of dogs and most of them barely escape into the library.
In Caroline's garage, Harlan and Caroline board the door into the house. As they get into Caroline's car to leave, along with her dog, Caroline realizes that she left the keys in the house. Harlan tries to hotwire the car, but before he succeeds, the sound of the dogs stop.