As soon as impoverished showboat captain Matt Lindsey pulls into his latest river town stop, he is confronted by Mr. Porter, the town clerk, who demands fifty dollars for a license. Fast-talking Matt buys Porter off with a bottle of hair tonic, but just before the boat's show is to start, Porter, furious that Matt's tonic has rendered him bald, returns with Sheriff Martin. The sheriff closes down the show and tries to arrest Matt, but is thwarted by an old Southern gentleman who pushes him into the river. While the sheriff struggles in the water, the boat chugs off to safety. Later that evening, however, the gentleman, who calls himself "Smitty," gets drunk at the helm and accidentally runs the boat aground just outside the town's swank hotel. When angry hotel owner Norris confronts Matt about the grounding, Smitty insists that the boat belongs to him and introduces himself as Colonel Jeffrey Witherspoon. After Norris calls the sheriff, he learns that Witherspoon is a rich eccentric who owns half the county, but whose face few people have ever seen. Witherspoon then startles Matt by giving him enough cash to pay for a tugboat and leaves for the next town to find one. In the hotel, meanwhile, guests Colonel Edward Beeler and his son John hear of Witherspoon's appearance and are reminded that the Beeler family has an old feud going with Witherspoon. Determined to renew the feud, which started when Witherspoon married Beeler's sister Penelope, Beeler telephones his other son Lionel, and orders him to bring Penelope and his trigger-happy cousin Ezra to the hotel. John, however, wants no part of his father's vengeance and goes to the boat to warn Witherspoon. While John meets Matt's attractive niece Midge, Matt, disguised as the bearded Witherspoon, enjoys a drink in the hotel bar. Unaware of what Witherspoon looks like, Beeler drinks with Matt and tells him of his murderous intentions but fails to mention his victim's name. When the Beelers and Norris then show up at the boat demanding Witherspoon, Matt, dressed as the colonel, obliges them until he realizes that Witherspoon is their target. Although Matt tries to explain his impersonation, the gun-toting Beelers refuse to believe him, and a frantic chase around the boat ensues. Matt removes his disguise, pushes the sheriff into the river and dashes back to the hotel. To avoid the enraged sheriff, Matt dons his disguise once more, but is shocked when Penelope arrives and identifies him as her long-lost husband. When Penelope, whose family tore her away from Witherspoon on their wedding night, insists on reviving her marriage, Beeler agrees to end the feud. To Matt's horror, however, Beeler then demands that Witherspoon go immediately to the bridal suite with Penelope. While the married Matt tries to stall the Beelers, Norris learns from bank manager Clay that earlier that day, Witherspoon withdrew a large sum of cash from his bank but never returned home. Matt, meanwhile, is forced into the bridal suite with Penelope, but manages to remove his disguise and sneak away. To avoid the sheriff, Matt re-dons his disguise and is identified by Clay as an impostor. Clay and the sheriff pursue Matt to the boat, and another chase ensues. The real Witherspoon returns in the nick of time and explains that he left his family in order to reunite with Penelope. After Witherspoon insists to the sheriff that Matt is his adopted son, Matt and his riverboat shove off for their next adventure.