Lorelei Lee is a gorgeous show girl engaged to become married into the wealthy Gus Esmond, much to the disapproval of Gus' affluent dad, Esmond Sr., who thinks that Lorelei is only after his cash. When Lorelei continues on a cruise followed solely by her best friend, Dorothy Shaw, Esmond Sr. hi res Ernie Malone, a private detective, to follow and report any questionable behaviour that could disqualify her out of the marriage.