Broncho Billy is sent on a secret mission to a small Arizona town. There he meets a beautiful girl, Elizabeth Barton, who is betrothed to a handsome daredevil, Juan Martin, of the Bar-O Ranch. Broncho is given a job by the foreman, George Chisholm. At a dance Martin and another cow-puncher quarrel. Martin draws his gun but Broncho Billy interferes. Martin is enraged and attempts to shoot Broncho. He takes the gun from him, takes the cartridges out and hands it back. Martin plots with the cook and other members of the outfit to poison the coffee of the foreman and steal the cattle. He hopes to throw the blame for the murder and theft on Broncho Billy.
