Penrod Schofield's mischievous dog, Duke, is falsely accused of biting Penrod's spoiled friend, Rodney. The real culprit is Snook, a dog belonging to Danny, the new kid in town who just coincidentally looks exactly like Penrod. Penrod and his gang of "junior G-men" want to hide Duke with a friend in a neighboring town, so they send Rodney on a wild goose chase with a messenger pigeon to get him out of the way. Duke is taken by the police before the gang can get him to the train station but escapes, and Rodney is captured by a real life "most wanted" gang for witnessing a payroll robbery. Penrod and his gang meet Danny and realize why Duke was blamed for the dog bite. When they go to the police to explain they learn of Rodney's predicament. They receive a clue from Rodney via messenger pigeon but are unable to convince the police, so they (including Danny) go to find Rodney themselves. Duke has managed to follow Rodney to the robber's hideout and gives away their location. The "junior G-men" rescue Rodney and capture the crooks.