A private eye is hired to protect a young woman who has a black book on a crime syndicate.

Architect Hal Norton and wife Meg invite his widowed mother Louisa to move in with them, only to discover the sweet elderly lady is romantically involved with what seems to be every old coot in town.

Robert Talbot, an American millionaire, arrives early for his annual vacation at his luxurious Italian villa. His long-time girlfriend Lisa has given up waiting for him and has decided to marry another man. Meanwhile, his sneaky business associate Maurice secretly misappropriates the villa as a hotel while Talbot is away. The current guests of the "hotel" are a group of young American girls.

Two dumb soda jerks dream of writing radio mysteries. When they try to pitch an idea at a radio station, they end up in the middle of a real murder when the station owner is killed during a broadcast.

Nightclub gangsters hire a vaudeville act called the Three Funny Bunnies (Ritz Brothers).

The story takes place at a summer theater in the Berkshire Mountains, where heroine Joan Barry (Carol Bruce) is staging a Broadway-bound musical comedy. Only one problem: two guest stars are shot and killed on two successive evenings, right in front of the audience. Hoping to solve the mystery, detective William Demarest demands that everyone -- actors and theatergoers alike -- return the following weekend to restage the show. But with no major performer willing to assume the fatal guest-star slot, Joan is forced to hire the Three Jolly Jesters (Al, Harry and Jimmy Ritz), Manhattan washroom attendants with showbiz aspirations.

Society sleuths Nick and Nora Charles investigate a murder in a jazz club.

When a US Naval captain shows signs of mental instability that jeopardize his ship, the first officer relieves him of command and faces court martial for mutiny.