I've shown my daughter a few silent Rin-Tin-Tin films recently, so we were both taken aback somewhat at how clunky and awkward this film often is compared to Rinty's silent work, but then early-sound films are often this way. Still, like most any Mascot serial, this is a fun film with a lot of action. Walter Miller, featured in a number of silent and sound serials, is a charismatic leading man (although at first he certainly does not seem to be the protagonist!!), even if his attempt at a Mexican accent sounds more like the bad pseudo-French accents one hears in pirate and Mountie films. Fortunately, June Marlowe (best-known for playing Miss Crabtree in the classic early 30's Our Gang shorts--by the way, I'd LOVE to see the two films Ms. Marlowe made in Germany in the late silent era. Are they around today??) doesn't even attempt a Hispanic accent, as Dolores Valdez, female lead in the serial, but she is attractive and charming and wears those "jungle pants" well. The cliffhangers are often impressive (although the resolutions of them aren't!), and in one chapter ending there are actually FOUR cliffhangers delivered at once, which is a wonderful touch! Rinty made one more serial for Mascot, THE LIGHTNING WARRIOR with Frankie Darro, which is also recommended. Like a number of 1930-31 serials that come to mind, there's a lot of mysterious eyes looking through secret panels and from behind corners, and lots of shadowy presences in the corners of the frame, which no doubt looked eerie up on the big screen at the theaters of the day. The Grapevine print is good quality, but is taken from a 1950's TV copy which has new credits. Also, I'm guessing that the first chapter was cut by a few minutes to fit into a thirty-minute TV slot, because there are a few continuity gaps (and scenes shown at the beginning of chapter 2 as recaps that WERE NOT seen in chapter 1!) that we didn't see in any of the later chapters. Every Mascot serial is worth watching, and this is no exception. Although hampered by the awkward early-sound technology, THE LONE DEFENDER should appeal to any Mascot serial fan...and any Rin Tin Tin fan or dog lover.