As one of the founders of the town of Lincoln, John Chisum is increasingly worried as Lawrence Murphy moves in on the local stores, bank and land by questionable means. Chisum and fellow honest ranch owner Henry Tunstall try and use the law, but Murphy owns that too. Confrontation threatens and Tunstall's man Billy Bonney is not slow to get involved.

An Irish bomber escapes from prison and targets a member of the Boston bomb squad.