The mysterious Cactus Kid (Lee Shumway) and his gang kill a prospector but do not discover the location of his gold mine. The prospector's dog Rinty (Rin Tin Tin) recognises the killers - though of course he can't tell anyone!
The Cactus Kid thinks the dog can lead him to the mine so tries to get his hands on the dog. Rinty meanwhile helps agent Ramon (Walter Miller) track down the identity of the Cactus Kid...
A decent enough serial with plenty of exciting cliff hangers. However, the story is maybe stretched a little too far in the serial format. The story probably would work better as a stand alone film, and indeed it was edited and reworked into such in 1934!
