Hopalong Cassidy (William Boyd), posing as a cattle buyer named "John Smith," arrives in the town of Dorado to investigate a series of highly efficient gold bullion robberies. The ongoing thefts, which target wagons leaving the local smelter, are driving the bank toward financial ruin, and the local sheriff has been unable to stop them.
While undercover, Hoppy must deal with the mayor's barbershop, which constantly plays comedy records, adding a peculiar backdrop to his investigation. He uncovers the corruption and works to break up the ring of thieves stealing the gold.
