Sharp as a Needle (1961)

Behind the backs of their antagonistic uncles--the headstrong owners of two swimwear companies, Thomas and Agamemnon--the inseparable lovebirds, Rena and Tonis, fall hard for each other. Unable to overcome the obstacles thrown their way, the love-smitten couple plucks up the courage to elope, and before long, the sworn enemies entrust the diligent private detective, Van Grey, with finding the missing young lovers. However, with the day of the annual contest for the best bathing suit rapidly approaching, will the cantankerous uncles set their differences aside for the sake of Rena and Tonis?