In the gay '90s, cardsharps take over a Mississippi riverboat from a kindly captain. Their first act is to change the showboat into a floating gambling house. A ham actor and his bumbling sidekick try to devise a way to help the captain regain ownership of the vessel.
Private eye Phillip Marlowe wants to get out of the detective racket and into crime writing. But when he's called to the office of editor Adrienne Fromsett, it's not to talk about his story ideas — she wants him to locate the missing wife of her boss, Mr. Kingsby. The assignment quickly becomes complicated when bodies start turning up.
A falsely convicted man's wife, Catherine, and an alcoholic composer and pianist, Martin team up in an attempt to clear her husband of the murder of a blonde singer, who is Martin's wife.