A wealthy young American woman is suddenly cut off by her father while living in Paris. A philosopher, she tries to make a living as a guide in the capital. The Marquis de Cernay, who has his eye on Nancy's portfolio, engages Maurice, a hardworking writer, to follow the young woman. She learns from both of them that they are only interested in her fortune. However, when she learns of the deception, she returns to her usual social life. She will return to him when the Marquis de Cernay has betrayed himself once and for all.

La fille d'un richissime américain prend son indépendance et s'installe à Paris, dans le Quartier Latin. Le Marquis de Servet, qui jalouse sa fortune, engage un écrivain sans le sou pour la surveiller. Mais celui-ci ne tarde pas à tomber amoureux.