Just before I sat down to write this review, I read through the featured review here on IMDb. Bkoganbing pretty much nailed it--explaining the plot and summing up the film. In fact, I suggest you just read their review--I haven't got much more to say....though I'll try.
This is a Johnny Mack Brown film and I generally enjoy his films because his B-westerns lack the frills and singing you'd usually find in one of these quickly maid films. Just like Tim McCoy, the film is simple and to the point and works because the hero isn't some pretty singing cowboy. While I enjoy an occasional Roy Rogers or Gene Autry film, realism is NOT a strong point in their films.
The film begins with Brown being an upright citizen in his town. Oddly, however, instead of being a cowboy or gunman, he's a clerk in a store owned by Al St. John (a frequent sidekick in westerns). But, when the sheriff is killed and a range war appears ready to erupt, Brown puts on the badge and aims to keep the peace--even though he harbors a dark secret. What is it and how it all works out, you'll have to see for yourself.
Overall, this is a very competently made film. It takes a VERY familiar plot and manages to breath some life into it. Well done and worth seeing.