The boys are working at the local boxing arena where their friend, Jimmy Higgins, is boxing. During a crooked match Jimmy is killed. The boys seek out his older brother, Johnny, a former boxer who gave up the sport rather than go crooked, and help train him to get back in the ring. They try to get him a shot at the title, and when they do the same crooked gangsters that were behind Jimmy's death try to get Johnny to take a dive.
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.
The Bowery Boys take on British crooks when one of them thinks he's inherited a title.
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.
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.
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.
When one of the Boys agrees to be hypnotized, he discovers he led a past life in the 1600s as a British tax collector.
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.
Sach receives news that he is the heir to the Terwilliger Debussy Jones fortune. Accompanied by his pal Slip, he arrives at the Jones mansion to review the legal papers needed for him to claim his new fortune. However, Sach and Slip discover that the rightful heir, the young Terwilliger III, is being cheated out his inheritance by the miscreant duo of Stuyvesant Jones and Clarissa. Sach and Slip, with the help of their fellow Bowery Boys, save the day and restore the heir’s inheritance.
Slip and the gang (Bowery Boys) foil foes of the exiled, incognito king of Truania (Sig Ruman).
A ghost helps the Bowery Boys capture a gang of crooks led by a mad doctor.
The Bowery Boys find a lamp that has strange magic powers.
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 the gang stray from newspaper work to detective work.
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.
One of the Bowery Boys gains superhuman strength, and he cashes in by becoming a pro wrestler.
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.
Slip and Sach's boss, David J. Thurston, has allegedly committed suicide. Slip finds a book of matches with the name of a local nightclub on his boss' desk and finds out from Gabe that a gambling casino is being run out of it. Slip comes to the conclusion that the club had something to do with his boss' death and sets out to find his murderer. The boys get jobs at the club and Louie poses as a rich cattlemen as they gather the information to convict the murderers.
While working in a laundromat, the boys find a baby hidden among the linen. They soon find out that the baby, who is the heir to a fortune, has been abandoned by his mother so that her two evil aunts can't cheat her and the baby out of the inheritance. The boys determine to help the woman claim her baby's rightful inheritance from her aunts, who have hired gangsters to find and eliminate the girl, the baby and anyone who helps them.
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.