Ben Frazer (Burt Reynolds) meets old flame Rose Traynor (Gena Rowlands) who is a passenger on the riverboat. The flame is rekindled as Rose and Ben interact romantically. As the plot develops, Ben discovers that Rose is deeply involved with a gang of gun smugglers who are secretly using the riverboat to further their evil plans. As Ben investigates the situation, the gang leader becomes alarmed and decides to kill Ben and take over the boat. Rose's feelings for Ben cause her to betray the gang in order to save Ben. A struggle ensues for control of the ship. Rose is shot while struggling with the gang leader for control of a gun. Ben then shoots the gang leader as the evil plot is foiled. Ben finds the fatally wounded Rose and she dies in his arms shortly after. The evil plot is foiled, and justice once again prevails on the river.