At the Bellomont, Lily and Mrs. Trenor are gossiping as usual. Mrs. Trenor tells Lily that Percy Gryce has left Bellomont because he felt snubbed when Lily canceled her walk with him to spend time with Selden. Worse, Gryce's departure may have been influenced by Bertha Dorset, who told Gryce about the "skeletons" in Lily's closet as well as her serious financial problems related to gambling debt. Lily thought she could simply spend one day with Selden and the rest of her stay with Gryce in at attempt to win him over, but her hopes of marrying him are not yet defeated. Still, she knows that Gryce has become a topic of conversation among the women at the Bellomont, most of whom find him disagreeable. Lily also realizes that she is accruing enormous debt from gambling and buying nice clothes, so she decides to return to the house of her aunt, Mrs. Peniston, as soon as possible.

Before leaving, Lily goes to the train station to pick up Gus Trenor, coming home to the Bellomont from a business trip. As they talk on the ride, the topic of Wall Street and investment comes up. Knowing that some of her friends have had success with stock market speculation, Lily decides to ask Trenor to invest some money for her. Trenor assents, although we later find out that he is interested in helping Lily because he is sexually attracted to her. Lily confesses to him that she is considering marriage to Gryce, about which Trenor expresses disgust. She admits that she needs more financial security and is no longer able to stay at the Bellomont.

The Wall Street speculation works initially; Lily begins receiving checks, which she uses to pay off her various gambling and clothing debts. She feels a sense of superiority over women such as Carry Fisher, who rely on the rich men with whom they flirt to pay off their debts. Several weeks after she begins investing, Lily's cousin Jack Stepney marries Gwen Van Osburgh. At the wedding, Lily meets Gerty Farish, a socially inept and generally disliked cousin of Selden who spends a lot time with him. Lily learns to her horror that Gryce and Evie Van Osburgh, the youngest Van Osburgh daughter, have been courting one another since they met at the Dorsets' house under the invitation of Bertha Dorset. Lily now knows that Bertha actively tried to prevent her marriage to Gryce.

Financially, Lily's investments continue to produce money; Lily receives another check for $4,000. Trenor invites her to return to the Bellomont to stay for several weeks, but Lily refuses his offer at first. He also encourages her to be friendly to Simon Rosedale, to whom Lily is ordinarily rude because she dislikes him intensely, as we see in a meeting between the two.

Chapter Nine introduces us to Mrs. Peniston and her house at Richfield, which Mrs. Peniston cleans thoroughly once every autumn. At her aunt's house, Lily has ample time to wander and think about her social situation, and she decides to stay away from the Bellomont until the Christmas holidays because the people there have become bored with her, knowing her too well.

Later that fall, Lily receives a visit from Mrs. Haffen, the woman who worked as a maid at the Benedick, where Selden lives. She presents to Lily a collection of letters written to Selden which he had not properly destroyed after reading. The letters, written by Bertha Dorset, are presumably love notes she wrote to Selden when they were having an affair (though this is never said explicitly). Realizing the letters could hurt Selden if they fell into the wrong hands, Lily purchases them from Mrs. Haffen and decides to destroy them. Before she can do so, however, Mrs. Peniston returns from Stepney's wedding and announces that Bertha was personally responsible for arranging the marriage between Evie Van Osburgh and Gryce. Realizing that the letters could also be used to blackmail Bertha, Lily decides to save them in her drawer so that they can be used to her advantage later.