As novice detectives, Bud and Lou come face to face with the Invisible Man.

Lou Costello plays a country bumpkin vacuum-cleaner salesman, working for the company run by the crooked Bud Abbott. To try to keep him under his thumb, Abbott convinces Costello that he's a crackerjack salesman. This comedy is somewhat like "The Time of Their Lives," in that Abbott and Costello don't have much screen time together and there are very few vaudeville bits woven into the plot.

In the gay '90s, cardsharps take over a Mississippi riverboat from a kindly captain. Their first act is to change the showboat into a floating gambling house. A ham actor and his bumbling sidekick try to devise a way to help the captain regain ownership of the vessel.

Molly, her brother, Slats, and his pal, Oliver, are taxi dancers at the Miramar Ballroom. As a publicity stunt, Slats plants an article about Molly claiming her ambition is to earn enough money to attend staid, all-girl Bixby College. Bixby's progressive dean offers Molly a scholarship. Molly accepts on the condition that Slats and Oliver come along too as campus caretakers. But the pompous Chairman threatens to foreclose on the school's mortgage if Molly isn't expelled. Together, the trio, with the help of some new friends, concocts a scheme to raise enough money to save the school. The plan involves a bet on the Bixby basketball team, which is playing in a game rated at 20 to 1 by the local bookie. But the bookie has other plans for their dough and hires a group of ringers to step in for the opponents. All is not lost, at least while Oliver has the chance to turn things around for his friends-one way or another.

Two bumbling plumbers are hired by a socialite to fix a leak. A case of mistaken identity gets the pair an invitation to a fancy party and an entree into high society. As expected, things don't go too smoothly.