The setting is Bath in the early 18th century. Beaucaire is posing as a barber employed by the French Ambassador. He is actually the Duc d'Orleans, the son of the King of France, a fact only known to his valet and his friend, Molyneux. Beaucaire is in love with Lady Mary Carlisle, who is herself courted by the Duke of Winterset. Beaucaire hosts a card game, where a number of gentlemen lose most of their money to him. In the second round, Beaucaire plays Winterset for high stakes. At the climax of the hand, Beaucaire exposes Winterset as a cheat. Winterset threatens to kill his opponent, but Beaucaire reveals that they are observed by his servants and the noble Molyneux. As the price of Beaucaire's silence, Winterset takes him to Lady Rellerton's ball to introduce him to Lady Mary.