Lorelei Lee is a beautiful show girl engaged to become wed to the wealthy Gus Esmond, much to the disapproval of Gus' rich father, Esmond Sr., who thinks that Lorelei is only after his cash. When Lorelei goes to a cruise accompanied only by her best friend, Dorothy Shaw, Esmond Sr. hires Ernie Malone, a private detective, to accompany her and report some other suspicious behaviour that could disqualify her from the marriage.