A prospector is murdered by The Cactus Kid and his gang, who hope to find the murdered man's goldmine. The miner's dog, Rin-Tin-Tin, recognizes the killers, who thereafter seek to use the dog to locate the lost mine. With the help of a government agent and a young girl, Rinty saves the mine and brings the bad guys to justice.—Jim Beaver <[email protected]>

As they return from their secret mine in the desert, prospectors Juan Valdez and Burke are ambushed. Burke escapes but Valdez is shot and killed. A notorious bandit, The Cactus Kid, is suspected of the crime. Ramon, actually a Justice Department Agent named Marco Roberti, a mysterious figure, overhears a conversation between two townsmen, Halkey and Jenkins in which they discuss their failure to get the location map of the mine from Valdez. Rinty, Valdez's dog,recognizes Jenkins as his master's killer and attacks him. Halkey, actually "The Cactus Kid", decides to capture Rinty as he thinks the dog can lead him to the mine.—Les Adams <[email protected]>