William "Steamboat Bill" Canfield is the owner and captain of a paddle steamer that has seen better days. He eagerly awaits the arrival of his college student son, whom he has not seen since the lad was a baby. Expecting a big, husky man like himself to help him compete with businessman John James King and his brand new, luxurious riverboat, William is sorely disappointed with his slight, awkward offspring, who shows up with a pencil moustache, a ukulele, and a beret. He becomes outraged when he discovers that his son and King's daughter Kitty, also visiting her father, are in love. Both business rivals are determined to break up the relationship.