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 of 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, 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
John Burrows, an ordained minister from a small village in the East, envisions himself with a larger congregation. He is mortified when his wife drunkenly interrupts a sermon, then despondent after her suicide. Burrows travels to Los Angeles for a fresh start, but takes to the bottle himself and ends up arrested for public intoxication. A skid-row con man, Gandy, finds him a bed at a flop house, while a street preacher, Doc Thorssen, and daughter Christine take him to a local mission. Christine is blind. She falls in love with Burrows, enjoying his discussions of the spirit and the soul but knowing little of his past. One day she is struck by a streetcar and knocked unconscious, causing Burrows to once again question his faith. He ultimately accepts the Lord's will and is offered a better place to live and preach. Burrows decides he is better suited to the mission, with Christine by his side.
Jan Horak is a middle-aged railroad dispatcher stationed at a forsaken spot in the desert, within driving distance of the nearest town. A widower, he has saved his money and goes to town to buy a dog, meets Betty, a flashy blonde who gains his confidence and marries him to acquire his $7,000 "fortune."
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.
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.
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.
Perry Ashwell is a self-satisfied child psychologist who takes his colleagues and wife somewhat for granted. So confident is he of his position that he introduces rich attractive painter Octavio Quaglini to his office and home. Quaglini is no respecter of convention, and April Ashwell is extremely attractive.
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 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.
Muggs' rich Uncle Pete is coming to visit. Unfortunately, Muggs' late father had bragged that he had seven kids, so Muggs recruits the members of the gang to pose as his family. Things turn sour, however, when a local mobster finds out about Muggs' deception and threatens to expose it.
A seemingly charitable soup kitchen operator (who moonlights as a criminology professor) uses his Bowery mission as a front for his criminal gang. Police attempt to close in on the gang as they commit a series of robberies, murders and bizarre experiments on corpses.
A Brooklyn pier racketeer bullies boat-owners into paying protection money but two fed-up fishermen decide to eliminate the gangster themselves rather than complain to the police.