Slick lawyer Thomas Farrell has made a career of defending mobsters in trials. It's not until he meets a lovely showgirl at a mob party that he realizes that there's more to life than winning trials. Farrell tries to quit the racket, but mob boss Rico Angelo threatens to hurt the showgirl if Farrell leaves him.

Lorelei Lee is a beautiful showgirl engaged to be married to the wealthy Gus Esmond, much to the disapproval of Gus' rich father, Esmond Sr., who thinks that Lorelei is just after his money. When Lorelei goes on a cruise accompanied only by her best friend, Dorothy Shaw, Esmond Sr. hires Ernie Malone, a private detective, to follow her and report any questionable behavior that would disqualify her from the marriage.