Rastignac is invited to Madame de Beauséant’s ball. The ball is a high point in the social calendar, and invitations are much sought-after. Rastignac notes that his cousin specifically mentions a desire to meet Madame de Nucingen, so he hurries to tell this to Delphine. She is pleased with the invitation, suggesting that this signifies their first step up the social ladder. Delphine mentions that her sister may also attend, dressed in her finest jewelry because recent rumors have suggested that she sold her family diamonds to cover debts accrued by her lover. That evening, Rastignac returns to the Maison Vauquer for what he hopes will be the final time.

The following day, Rastignac clears his room in anticipation of his departure from the boarding house. Among his possessions, he finds the note promising to pay a debt to Vautrin. As he is about to destroy the note, he hears Delphine talking to her father, Goriot: She is explaining to him that her husband has invested all their money in speculative assets. He cannot access the money or give it back to her, he says, but he has promised to repay her in two years with interest.