After the visit to Maud's place, Milly basks in the glow of her social success. Susan assures her that she was the most admirable person at the party. Susan goes on to think about how wonderful their experience in London is going to be. The only problem is that she can't think about how much Milly will love it without feeling bad about her illness.
Milly mentions to Susan that she's certain Kate Croy has some sort of secret that is weighing on her mind, and she is pretty sure that the secret involves a man. For the rest of the week, Milly can feel the shadow of this unnamed man hanging over Kate Croy.
During the week, Milly is offered all kinds of opportunities to go to museums and operas, but she really just wants to hang with Kate and have her tell him all about herself and Lord Mark. It's funny, because Lord Mark wants her to find out about Kate for him; but she's actually finding out about him through Kate.
Kate simply answers that Lord Mark and Aunt Maud have an understanding with one another and that they work for mutual benefit. What she's really saying is that Aunt Maud is trying to set Lord Mark up with Kate.
Kate goes on, though, to tell Milly that she won't meet any greater woman in London than Maud Lowder. During this week, Milly also feels herself drifting away from Susie because she (Milly) now has a new, younger friend in Kate.
As more time passes, Milly begins to see how London is full of secret dangers and all kinds of subtle power moves that one would never even dream of back in the what-you-see-is-what-you-get United states.