Frankie, a soda jerk in the hick town of Midvale, is quietly tending to his sodas when a big time gangster stumbles, wounded, into the drugstore and dies. Because the gangster was a participant in a $300,000 bank heist, Frankie and his friend Jefferson, the hotel porter, are besieged by more gangsters, the town sheriff and Gerry, a newspaper reporter, who all assume that the gangster told him where the money was hidden. When another gangster is murdered, Frankie, a budding scientist and detective, decides to take matters into his own hands and trick the murderer into revealing himself. He decides to trap the killer by making him believe that Jefferson knows his identity, and as the porter reluctantly wends his way to the sheriff's office to identify the murderer, Frankie awaits in ambush for the real killer to tip his hand. The terrified Jefferson bungles Frankie's plans though, when he inadvertently overturns some shipping crates, thus allowing the murderer to escape. Fortunately, in one of the crates, Frankie finds a clue which exposes Cyrus Haddon, the town banker, as the mastermind behind the holdup.