Dora arrives at the party. Guido sees her and realizes she's the poor woman marrying Rodolfo.
Guido runs into Dr. Lessing checking out of the hotel. The two say goodbye, complementing each other on their wit and culture. Dr. Lessing gives Guido a riddle as a parting gift: "If you say my name, I'm not there anymore. Who am I?"
Guido solves it soon after Dr. Lessing leaves: "Silence."