John Chisum, a virtuous, patriarchal land baron, locks horns with greedy Lawrence Murphy, who will stop at nothing to get control of the trade and even the law in Lincoln County, New Mexico, New Mexico Territory.
When a crooked sheriff murders his employer, William "Billy the Kid" Bonney decides to avenge the death by killing the man responsible, throwing the lives of everyone around him into turmoil, and endangering the General Amnesty set up by Governor Wallace to bring peace to the New Mexico Territory.
When his cattlemen abandon him for the gold fields, rancher Wil Andersen is forced to take on a collection of young boys as his cowboys in order to get his herd to market in time to avoid financial disaster. The boys learn to do a man's job under Andersen's tutelage, however, neither he nor the boys know that a gang of cattle thieves is stalking them.
Following the Civil War, headstrong rancher Thomas Dunson decides to lead a perilous cattle drive from Texas to Missouri. During the exhausting journey, his persistence becomes tyrannical in the eyes of Matthew Garth, his adopted son and protégé.
Three of the original five "young guns" — Billy the Kid, Jose Chavez y Chavez, and Doc Scurlock — return in Young Guns, Part 2, which is the story of Billy the Kid and his race to safety in Old Mexico while being trailed by a group of government agents led by Pat Garrett.