Although Tom Tyler is the nominal lead in this early RKO sound short, the real star is Mona Ray, the eponymous Polly of the movie. She shows up and with the MacFarlane brothers, does some nice trick shooting and roping, then ride to the rescue of Tyler, who's been kidnapped to prevent him from winning a jumping race upon which a lot of money has been wagered.
Apparently this was expanded into a feature, mostly by replacing everyone but Miss Ray and the MacFarlanes and putting in a few musical numbers. I'd like to see it some day.
Although the impetus of this movie is largely to show off little people qua little people, and so is not liked on kindly these days, it should be pointed out that they are the actual heroes of the movie.
