A series of ghastly murders are being committed. The one similarity in each of the murders is that a strange buzzing sound is always heard right before the murder occurs. Is the killer invisible or possibly some other incredible creature?
Burglar Nat Harbin and his two associates set their sights on wealthy spiritualist Sister Sarah, who has inherited a fortune -- including a renowned emerald necklace -- from a Philadelphia financier. Using Nat's female ward, Gladden, to pose as an admirer and case the mansion where the woman lives, they set up a perfect break-in. Things get complicated afterwards.
An escaped murderer flees France to England, where he forces an ex-forger, now established as a reputable estate owner, and the forger's daughter who knew nothing of his past, to counterfeit 5-pound notes for mass distribution around the countryside.
An artist suffering from mental problems from his experiences during the war goes to Acapulco on his honeymoon. Soon young women are turning up dead in the area, and the ex-GI comes to believe he might be responsible, as he has long stretches where he can't remember anything.
A newspaper publisher, wanting to prove a point about the insufficiency of circumstantial evidence, talks his possible son-in-law Tom into a hoax in an attempt to expose ineptitude of the city's hard-line district attorney. The plan is to have Tom plant clues leading to his arrest for killing a female nightclub dancer. Once Tom is found guilty, he is to reveal the setup and humiliate the DA.
In Paris, Bob Montagne is practically synonymous with gambling -- and winning. He is kind, classy and well-liked by virtually everyone in town, including police inspector Ledru. However, when Bob's luck turns sour, he begins to lose friends and makes the most desperate gamble of his life: to rob the Deauville casino during Grand Prix weekend, when the vaults are full. Unfortunately, Bob soon learns that the game is rigged and the cops are on to him.
When Johnny Matlock whisks away a cold war secret from under the noses of Berlin's top secret agents, his every move is followed when he returns to England. His girlfriend Paula is kidnapped but her handbag is discovered at the scene of the crime by the aristocratic private eye, Duke Martin. Inside it he discovers the secret formula that the agents are searching for and tracks down her sister Paula. As Johnny grows frantic for the safe return of his girlfriend, Duke Martin plays a deadly game of double bluff with the enemy agents.
Career criminal Johnny Clay recruits a sharpshooter, a crooked police officer, a bartender and a betting teller named George, among others, for one last job before he goes straight and gets married. But when George tells his restless wife about the scheme to steal millions from the racetrack where he works, she hatches a plot of her own.
When illegal card dealer and recovering heroin addict Frankie Machine gets out of prison, he decides to straighten up. Armed with nothing but an old drum set, Frankie tries to get honest work as a drummer. But when his former employer and his old drug dealer re-enter his life, Frankie finds it hard to stay clean and eventually finds himself succumbing to his old habits.
Gambler Nathan Detroit has few options for the location of his big craps game. Needing $1,000 to pay a garage owner to host the game, Nathan bets Sky Masterson that Sky cannot get virtuous Sarah Brown out on a date. Despite some resistance, Sky negotiates a date with her in exchange for bringing people into her mission. Meanwhile, Nathan's longtime fiancée, Adelaide, wants him to go legit and marry her.
A hugely successful DA goes into private practice after sending a man to the chair -- only to find out later he was innocent. Now the drunken attorney only seems to represent criminals and low lifes.
Davey Gordon, a New York City boxer at the end of his career, falls for dancer Gloria Price. However, their budding relationship is interrupted by Gloria's violent boss, Vincent Rapallo, who has eyes for Gloria. The two decide to skip town, but before they can, Vincent and his thugs abduct Gloria, and Davey is forced to search for her among the most squalid corners of the city, with his enemy hiding in the shadows.