The Bowery Boys--Slip, Sach, Bobby, Whitey & Chuck--start their own exterminating service, and get a job which takes them to a spooky old abandoned mansion in the middle of the night. Meeting up with pal Gabe and his new French bride, the boys are tormented by mad scientists who try to convince them the place is haunted and then kidnap Sach in order to place his brain inside a gorilla.
Slip (Leo Gorcey), Sach (Huntz Hall), Bobby (Bobby Jordan), Whitey (William Benedict) and Chuck (David Gorcey) unsuccessfully try to sell a dilapidated car to a street cleaner for a fabulous amount, so they can get enough money to save Louie's (Bernard Gorcey) Malt Shop. Sidewalk photographer Cathy Smith (Teala Loring) snaps a pictures of three bank robbers as they are fleeing a robbery but when the Bowery Boys and Cathy realize that Sach is also in the photograph, they break into the photo lab to destroy the negative, which might make the police think Sach was involved in the robbery.
The Bowery Boys head west to clear Louie of an old murder charge that he had killed his gold-mine partner. Sach has the map to the gold mine painted on his back, and Blackjack McCoy has him kidnapped by Indian Joe. Gabe poses as a dangerous gunman, the Klondike Kid, while Slip is in charge of all the remaining loose ends.
Slip, Sach and the rest of the Bowery Boys enter a haunted house, where they engage in slapstick with a gorilla, a robot and a vampire
The Bowery Boys find a lamp that has strange magic powers.
In order to be able to get the names of winning horses at the track, Sach agrees to sell his soul to the devil.
Slip and Sach are working for a local newspaper as a reporter and photographer, respectively. Slip wants to get the goods on a local gambling ring that is fixing sporting events, so he and Sach go undercover to expose the ring.
When Sach eats too much sugar, he goes into a trance whereby he's able to predict the future. Slip tries to make some money off of Sach by using him as a fortune teller in a carnival, until a mad scientist kidnaps Sach to use him in an intelligence-switching experiment with a monster.
Slip, Sach and the gang think an air-raid test is for real and join the Army.
The Bowery Boys open a nightclub after Sach has his tonsils out and wakes up with a singing voice.
The Bowery Boys tangle with Scotland Yard, diamond smugglers and a gem-toting canine during an ocean cruise.
While Louie is on vacation, the boys turn The Sweet Shop into an escort service, and soon find a group of beautiful girls as their first clients.
When a cold medicine causes Sach to be able to smell diamonds, he and the rest of the Bowery Boys are induced by a diamond dealer to accompany him to Darkest Africa in search of a legendary cache of them.
One of the Bowery Boys gains superhuman strength, and he cashes in by becoming a pro wrestler.
Sach and the gang baby-sit a bratty TV star.
Slip and the gang foil foes of the exiled, incognito king of Truania.
Sach and the gang (Bowery Boys) find stashed cash in an old farmhouse apparently haunted.
Slip and Sach go to prison to help a reporter with a story.
Slip gets fired from his job at a construction company for decking his boss. His sister, who got him a job at the company, is angry with him. Slip manages to get a job with the District Attorney serving warrants, as does Sach. Through his job, Slip finds out that all is not quite kosher at his old construction company, and that his sister may be in danger.
Slip has entered the Boys' rattletrap car in a souped-up jalopy race, but has no chance of winning until Satch, with the aid of a scientist acquaintance, comes up with a chemical concoction that acts as a super-fuel; but a rival entrant in the race learns of this and tries to get the formula for himself.