Lord Mark asks Milly to accompany him to a private room in the house where there's an old picture of a woman who apparently looks just like Milly.
As they move through the house, Lord Mark passes a bunch of people who know and greet him. Milly knows that they're curious about who she is and why she's walking alone with him.
As they go through more and more winding corridors, she becomes aware that there's some other reason Lord Mark wants to get her alone. It's as if he has something he wants to say to her.
When she sees the portrait that Lord Mark wants to introduce her to, Milly finds that she can't help but cry. The woman in the painting is beautiful, and yes, she looks like Milly. But Milly also knows that this woman must be long dead (it's an old painting) and Milly has had some major issues with death in recent months.
She strangely claims, "I shall never be better than this" (22.214.171.124). Lord Mark insists that she's probably much nicer than the woman in the picture ever was. But she corrects him and says what she really means, which is that she'll never have another afternoon as beautiful as the one she's having, and that she's glad that he (Lord Mark) is a part of it. Lord Mark doesn't understand what she means, but acts as though he does.
Milly goes on to argue that she's not as lovely looking as the woman in the picture. But Lord Mark turns her around and she sees Kate Croy entering the room with two people. Before Lord Mark can say anything, Kate Croy exclaims, "You had noticed it too?" This pretty much confirms that Milly is the spitting image of the woman in the painting.
A woman tries to ask Milly over for dinner, but Lord Mark interrupts her and saves Milly from the invitation.
When she gets a free moment with Kate, Milly asks for a favor. She needs to deceive Susan Stringham about something. Kate agrees. It turns out that Milly wants to pay a visit to a famous English doctor in the coming week and doesn't want Susan to know about it. She wants Kate to come to the appointment with her.
Kate asks what's wrong with her, but Milly doesn't give a straight answer. Kate agrees to go, then tries to comfort Milly by saying that she's in the prime of her life and that she can do anything. Milly might be getting tired of hearing that, though.