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.

• Mascot Pictures
• Rin-Tin-Tin
• Walter Miller
• June Marlowe
• Josef Swickard
• Buzz Barton
• Lee Shumway
• Julia Bejarano
• Lafe McKee