May 8th, 1945 - England is celebrating its victory. Cloistered away in Buckingham Palace, Princess Elizabeth and her headstrong 15-year-old sister Margaret would give anything to join the party and spend one night where no one knows who they are. The King and Queen give them permission to go out until midnight, accompanied by two Royal Guardsmen. Arriving at the Ritz Hotel, Margaret escapes, whisked away by a group of partying naval lieutenants, and Elizabeth decides to chase after her fun-loving sister. Daunted by the exuberance of the city, the anxious and vulnerable Elizabeth ends up falling into the arms of a young airman, Jack. He is unaware of Elizabeth's true identity and she has no idea Jack has gone AWOL from the military. Over the course of the night, this unlikely couple searches for Margaret through the West End.