Mac Brewster of Brewster Advertising Agency has been named chairman of the Artists and Models Ball and must choose a queen for the event.  In exchange for a million dollar ad campaign, Mac promises Alan Townsend of Townsend Silver that he will make the yet-to-be-found "Townsend Silver Girl" queen of the ball.  Mac then promises his girlfriend, Paula Sewell, a working class model, that she will be the queen.  Alan, however, wants to use a girl who has stepped out of the social register, not an actress.

Consequently, when Cynthia Wentworth of Park Avenue visits him at his office selling tickets to a charity, he offers her the Townsend Girl title.  Mac, meanwhile, proposes to Paula, and they become engaged.  Deciding she has the "clothes and the nerve" to pose for Alan, Paula goes to Miami under the name Paula Monterey and hob-nobs with the rich.  Paula charms Alan and, after they dance, they end up taking a midnight dip in the pool together, at which point Alan calls Paula "Cinderella."

Meanwhile, Mac meets Cynthia and assumes she is a model.  When she reveals that she is one of the Park Avenue Wentworths, he names her the Townsend Girl.  In Miami, Paula upholds her façade as a society girl, and Alan names her the Townsend Girl.  The two couples then reunite in Miami, and Mac learns that Alan has already promised the job to Paula, with whom he has fallen in love.

Later, Paula breaks her engagement with Mac, admitting her love for Alan.  Alan's mother then discovers Paula is a professional model, causing Alan to think Paula has used him; but he allows her to remain the Townsend Girl.

Two months later, on the night of the ball, both Cynthia and Paula propose to Mac, planning to announce his answer at the ball.  At the ball, Paula's roommate, Toots, tells Alan that Paula is in love with him, and Paula and Cynthia each choose the man they will announce that evening.  At the stroke of midnight, Paula, as the queen, loses her shoe, and Alan appears in costume to replace it, telling her she is the Townsend Girl.  Both happy couples then march off stage.