Rustlers On Horseback has a bit more plot to it than the usual B western from Republic. US Marshal Rocky Lane through a streak of good fortune has his prisoner killed by outlaws and then is mistaken for that prisoner. Which allows him to infiltrate the gang his prisoner was traveling to join for a bit of undercover work.Good thing too because the outlaw gang that Roy Barcroft leads has quite a scheme in mind for a place that Barcroft murdered the owner to acquire. It makes a perfect hideout for an outlaw gang. But there is also Forrest Taylor who is bringing over a $100,000.00 to buy parcels of land for a new settlement. The idea is to steal his money and keep the ranch. And Barcroft is the muscle, there's a different guy who is doing the planning.As these type westerns were meant for the Saturday matinée kid crowd usually the emphasis is on action. Action there is, but this one also has an interesting story line for us older kids as well.

Marshall Rocky Lane is mistaken for his deceased prisoner Clune, who was killed by the same gang he has now joined. The gang, headed by an unknown leader and taking orders from Straykin, killed a deputy marshall who was a good friend of Lane's. The next move for this gang is to rob Taylor, an easterner, of $125,000 which he plans to use to purchase a ranch, which rightfully belongs to Reynolds, who is using an alias in order to get close to Straykin's gang, who also killed Reynolds' father, in order to get the ranch. Its up to Lane, his friend Nugget Clark, to round up the outlaws before they make off with the money. As usual, a good entry in the Rocky Lane series. The movie starts off a bit slow, but builds energy as it goes along, with a nice climax at the end. The "unknown leader" gimmick is wasted here since it's pretty easy to figure out who it is, even before he's revealed halfway into the film. One of Brannon's better directorial efforts. Rating, based on B-westerns, 7.