Tad and Tim McPherson are members of a ruthless gang of rustlers and robbers known as the Paint Horse Riders, who operate out of Silver City, Arizona in 1885. Although Colonel Charles Ormsby has organized a group of vigilantes and offered a reward for the capture of the killers, they remain at large, mainly because Ormsby is their leader and is in cahoots with Sheriff Judell. The governor sends ranchowner Tom Munroe to clear out the criminals, and on his way into town, Tom arrests four of Ormsby's gang for stealing ponies from an Indian reservation. In his hotel room, Tom is startled when bullets are shot through the floor, and rushes downstairs, half-dressed, to find drunken cowboy Lucky Dawson shooting his gun at random. He befriends Lucky and then runs into rancher Norma Laird on his way back to his room, but is embarrassed because he forgot his pants. The next day, Sheriff Judell reports that Tom's prisoners have escaped and stolen all the horses in Lucky's stable, including Tom's horse, Tony. Lucky and Tom have dinner with Norma, but Tom leaves when he hears his horse outside and finds Norma's brother Bernie, also known as "Little Casino," with the stolen horses. After yet another stagecoach robbery, Tom follows the outlaws to their hideout and arrests Bernie, Tad and Tim. Ormsby again helps his men break out of jail, and Bernie heads to Norma's ranch to hide. He confesses his misdeeds to his sister, but Ormsby and the gang are afraid he is going to squeal on them and follow him there. Tom arrives and claims Bernie as his prisoner, and the outlaws open fire against the ranch house. Ormsby, who has been inside with his vigilantes, goes outside on the pretense of talking with the criminals, and Bernie reveals to Tom that he is the head of the operation. Tom sneaks out and notifies Lucky to send help, then he saddles up some wild broncos for the rustlers. When Lucky arrives with help, the rustlers try to escape, but are bucked off their horses and all, including Ormsby, Tad and Tim, are arrested. With Ormsby out of the way and Bernie paroled, Tom and Norma get to know one another better.