In 1803, Napoleon Bonaparte is negotiating with the United States for the sale of the Louisiana territory. He sends his brother Jerome to America as his ambassador. Arriving incognito at the races in Baltimore, Jerome meets Betsey Patterson, the attractive daughter of Charles Patterson, one of the negotiators. Still in disguise, he applies for the job of her French tutor, and the two fall in love. Jerome, however, is fired from his tutoring job for defending Napoleon too vigorously. After the Louisana purchase is completed, Jerome returns to the Patterson household as himself. The Pattersons are slightly embarrassed, but welcome him. Some time later, Betsey and Jerome announce their engagement, to the dismay of Jerome's counselors, who have received word that Napoleon wants Jerome to return to France to marry the Princess of Wurtemberg, a political alliance that will help Napoleon in the war he is fighting against England. Jerome refuses and sets sail for France with Betsey, intending to marry her once they land, but Napoleon meets the ship and, speaking privately to Betsey, asks her to give Jerome up for the good of France. At first, she will not agree, but finally she leaves without saying goodbye to Jerome. She resigns herself to a lonely life without Jerome. He, however, cannot do without her and follows her back to America.