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.
Leo GorceyTerrence 'Slip' Mahoney
Huntz Hall'Sach' Jones
Mike MazurkiPatsy 'Pat' Clark
Bobby JordanBobby
William BenedictWhitey (as Billy Benedict)
William FrambesHomer
Claudia DrakeJeanette
Pamela BlakeMary Mahoney
John EldredgeHerbert L. Sayers
Bernard GorceyJack Kane
After Slip is drafted into the Marines, the rest of the gang volunteers so they can be with him. Sach discovers that the colonel knew his father and he is promoted. During a drill that he is putting the rest of the gang through, they find a soldier left for dead on the side of the road. Slip discovers a playing card next to the marine and traces it to Jolly Joe Johnson's gambling house. They suspect that the gambling house is cheating and set out to uncover the proof.
Dr. Tom O'Hara takes over a public clinic in New York's desperately poor Bowery section. Boy gangleader Sock Dolan resents Tom's interference in moving Sock's kid brother to a hospital, because Sock blames hospitals for his mother's death. Sock helps racketeer J.R. Mason sell food to the clinic, unaware that Mason sells cheap and often tainted food. When a number of patients, including Sock's brother, become ill from food poisoning, Sock is kidnapped by Mason to keep him silent. Dr. O'Hara must find a way to rescue Sock and stop Mason's contamination of hospital food supplies.
The Bowery Boys find a lamp that has strange magic powers.
A man wins $50,000 in a card game with gamblers, but is soon found dead and the money missing. Slip and Sach find the money near where the body was discovered, and soon find themselves the target of both the police and the gamblers.
Sach is given a post-hypnotic suggestion that turns him into a championship prizefighter.
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.
The Bowery Boys are enrolled in a fancy college by a pair of rich snobs who think they can turn the Boys into classy guys. Sach becomes a football star, and is kidnapped by gangsters to keep him out of the big game.
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.
Sach is the exact double of a famous French scientist who has invented a powerful rocket fuel. Enemy agents, mistaking Sach for the scientist, attempt to kidnap him and get the formula for the fuel.
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.
The Bowery Boys take on British crooks when one of them thinks he's inherited a title.
A ghost helps the Bowery Boys capture a gang of crooks led by a mad doctor.
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 invites his cousin Jimmy to stay with his family after he is released from prison. However, Jimmy soon gets mixed up with an auto-theft ring.
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
Slip and Sach take the rap for a robbery they did not commit in order to uncover the real robbers, whom they suspect are led by a convict who gives orders to his gang outside via a short-wave radio stashed somewhere in the prison.
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.