In Paris, France, Robert de Bellecontre, the son of a nobleman, is betrothed in infancy to Simone de Villeneuve. Seventeen years later, Robert meets Nancy Worthington, an American tourist, and they are accidentally locked in a museum overnight. By the next morning, they are in love, but when Robert confesses his engagement to Simone, Nancy exits in tears. Later, at the Bellecontre chateau, Nancy stages a false automobile wreck and gains entrance to the house. She then learns that Simone is in love with her father's secretary but will not embarrass her family by breaking the engagement. Nancy engineers a proposal from Simone's father and agrees to marry the marquis only if his daughter's engagement to Robert is broken. When this fails, Nancy stages a mock struggle in Robert's room, causing his father to demand that the youngsters marry to protect the family name.