After losing her job as a waitress, Mary Ryan is hired to work in a traveling show's chorus line by theatrical agent Leon O'Day and his partner. The agents convince a young, wealthy socialite named Seymour to finance a brand-new show. To secure the gig and the funding, they lie to Seymour and tell him that Mary is actually a Russian princess in hiding. The deception completely charms Seymour, and Mary gets her contract. Her fabricated royal status takes off when Seymour's mother invites Mary to tea, catapulting her to society stardom. However, the lie threatens to unravel when Mrs. Seymour—an avid social reformer—takes Mary and Seymour to a night court, where Mary's missing sister Rose is brought in under arrest. When Mary claims her sister, the truth is exposed, leading to a series of complications and dramatic resolutions.