Plot
Jim Cole, his wife Angela, along with their children Charlie and Gypsy, niece Meg, and his friend Sam Potts arrive in a small Wyoming town. Jim inherited a ranch from his late uncle and quit his job as a lawman to become a rancher. In town, banker Mr. Benson mentions a $675 mortgage on the property. Jim hesitates to take the land title, since it would take nearly all their savings, but eventually relents. Rancher Jed Curry initially owned the property but lost it to Jim's late uncle in a card game and wants it back.
In the countryside, the Coles arrive at the ranch's cottage, which is nothing more than a tumbled-down shack.
The next morning, as Jim is building a fence, Benson warns him of Satan, a grizzly bear who invades ranches and kills livestock for fun. Many have tried to kill him, to no avail. Jed tries to persuade Jim to sell the land, but he refuses.
Jim returns to town the next day and asks Wilhelmina Peterson, who owns the general store, if she knows where he can buy cattle to breed with his prize bull Duncan. She asks her sidekick Hank to bring Jim to Hazel Squires' place. There, Hazel says that she can sell cattle for a buck each. When she goes to a pen to check on the pigs, she finds them all missing or dead; it is the work of Satan.
During the night, Satan reaches the Cole place, killing Duncan, causing Sam's mule to run away, and badly injuring the family's dog . The next morning, while the doctor stitches up the dog, Jim and Meg go to the store for coffee. However, the Curry boys are there with cohorts and start harassing Jim. A fight starts, with the Curry sons driven out. Jed later chastises his sons, telling them not to antagonize Jim if they are to get his ranch.
Needing a replacement bull but with no money to buy one, Jim is compelled to get a loan from the bank, giving Benson various possessions as collateral. He goes to the Squires ranch to purchase the bull and cattle for breeding. After learning of the loan, Jed warns Benson not to do it again and reminds him that he, as the major stockholder of the bank, has the authority to do this.
While working on the farm, the Coles and Sam see the mule appear. However, it is badly-injured, dying minutes later. Distraught, Sam and Jim vow to kill Satan.
While tracking Satan through the woods, Jim and Sam are attacked, but escape by jumping off a cliff into a lake. As the Coles return home from a dance social, they find that Satan has killed most of their cattle. Again, Jim goes to Benson for a loan to buy replacement animals, but this time, Benson refuses his request. Satan's depredations reach a crisis point, and Jed posts a $750 reward for anyone who can kill the bear. Because of this, bounty hunter Cass Dowdy appears in town with hunting dogs. Jim had sent Cass to jail for two years for murder. Cass plans to hunt the bear just to make sure Jim will not get the reward money and thus ruin him financially.
Jim and Sam set a trap for Satan. The men doze off while waiting, and Satan attacks again, driving off one of the horses and killing Sam. Dowdy's dogs are also killed by Satan. More traps are set up for Satan, to no avail. One night, Dowdy visits one of Jim's traps to sabotage it but is accidentally injured instead. The next morning, the two meet again and fight, with Jim winning and leaving Cass there.
At home, Angela tells Jim that she no longer wants to live there and will leave if he continues to hunt Satan. She eventually calms down when he says he is killing Satan to protect his family. The next morning, he finds that Charlie has gone after Satan alone. Jim follows Charlie into the woods.
In the woods, Jim once again runs into Dowdy, who almost kills him. However, Jim fights back and drives him away. At night, Satan attacks Charlie and chases him up a tree. Charlie jumps out of the tree and distracts Satan, while Dowdy fires at the bear to save the boy, but is fatally mauled. Jim then injures Satan and shoots him dead. After comforting a dying Dowdy, who sacrificed himself to save Charlie, Jim and Charlie return home.
