Karl Westover, played by actor Gary Busey, is a young farm boy who accidentally kills a neighbor after a dispute. The neighbor's family, seeking vengeance, begin to pursue Karl. Fearing for his life, Karl runs away from his home and family and seeks refuge in the Texas wilderness.
While on the run, Karl stumbles upon Barbarosa, played by actor Willie Nelson, a legendary gunman who has become a legend due to his often violent and fierce reputation. Barbarosa is hiding out from his father-in-law, Don Braulio, played by Gilbert Roland, a wealthy Mexican rancher who disapproves of his daughter's marriage to Barbarosa. Braulio has hired a group of bounty hunters to kill Barbarosa.
Despite Barbarosa's initial reluctance, Karl convinces him to take him on as a partner and teach him how to survive in the wilderness. Karl is clumsy and inexperienced, but he eventually proves his worth to Barbarosa. The two men form an unlikely bond as they face danger from both the bounty hunters and from Braulio's henchmen.
Along the way, Barbarosa and Karl encounter several colorful characters, including a group of bandits and a beautiful woman named Isela, played by Danny De La Paz. Isela is Don Braulio's niece and she becomes romantically involved with Karl, adding another layer of tension to the already complicated situation.
As the two men try to stay one step ahead of their pursuers, they must also confront their own personal demons. Barbarosa struggles with his past, while Karl tries to come to terms with the guilt he feels over accidentally killing his neighbor.
Ultimately, Barbarosa and Karl are able to outwit their enemies and escape with their lives. The film ends with the two men parting ways, each heading off into the unknown future.