Don travels to Columbia with Rosie on Tuesday. He had previously emailed a work acquaintance at Columbia, David Borenstein, though he had not yet responded. Rosie meets with Mary Keneally, a psychiatry professor, to discuss her dissertation research topic: the environmental origins of early-onset bipolar disorder. Don is fascinated by this topic and Rosie’s thoughtful approach to her studies. Mary encourages Rosie to switch to medical school and introduces her to the dean of the school of medicine, who coincidentally turns out to be David Borenstein. They all have lunch together, and David tells Don that there is a job for him at Columbia any time he chooses.

That night, Don asks why Rosie didn’t pursue medicine like Mary suggested. Rosie tells him that she had considered it and actually did get a 74—an extremely high score—on her medical school entrance exam like she said when they met with Dr. Enticott. However, she felt pursuing medicine would prove she had an “obsession with [her] real father” (219). Don doesn’t understand her reasoning, but he doesn’t challenge her on it.

On Wednesday, Don escorts Rosie through the Museum of Natural History, explaining the exhibits and trying to make the visit interesting for her the way she had made her chosen activities interesting for him. Rosie loves the exhibits, and they stay until the museum closes. Moved by the Heilbrunn Cosmic Pathway, which is a representation of the universe’s age, she takes Don’s hand as they leave and holds it all the way to the subway.

Don and Rosie have one last task in New York: collecting a DNA sample from Max Freyberg, a plastic surgeon. They are posing as a journalist (Rosie) and a photographer (Don) who want to interview Freyberg for a series on successful graduates of their university. 

The interview seems to be going smoothly, as Rosie asks thoughtful questions, but there is no window for them to retrieve a sample. Then, the meeting takes a turn when Don and Rosie give different answers for the name of the magazine. Freyberg suspects that they have an ulterior motive, so Don escapes to the bathroom to create a diversion. While there, he collects a DNA sample because of Freyberg’s terrible hygiene. Don texts Rosie to get out of the office, and he escapes by climbing out of the window and scaling the side of the building. Rosie is waiting for him at the bottom, and she reveals Freyberg thought they were private detectives investigating him on behalf of disgruntled patients.

Back at the hotel, Don goes to Rosie’s room when she takes too long to get ready for dinner. She answers the door wearing only a towel, and Don is unable to keep himself from observing her. As a result, they discuss the value of appearances, with Don saying they don’t matter while Rosie thinks that it’s important to the ego to look good. He says knowing that she is “incredibly beautiful” (227) seems incongruous to being a feminist. When he brushes her hair aside to surreptitiously examine her earlobes—Gene once told him earlobe size correlated with sexual attraction—Rosie kisses him. 

Rosie admits that she finds Don attractive, and he assumes that she wants to have sex. When he prepares to kiss her again, she tells him that this will be a one-time occurrence. Don excuses himself on the unspoken pretext of getting a condom and returns to his room to shower and consult the book of sexual positions that Gene gave him. Returning to Rosie’s room 43 minutes later, he confesses that his inexperience means she should be the one to choose the position, and he hands her the book. Recognizing Don’s signature underneath the short inscription he left, Rosie says that she’s changed her mind about having sex. Don is worried he has done something wrong, but she reassures him that he hasn’t and he leaves.

Very confused about the events, he calls his baseball friend, Dave, and they go out for pizza to talk about women.

The next morning, Don manages to get himself on the plane to their connecting flight in Los Angeles. He is completely overwhelmed emotionally and needs time to think through all that has happened, particularly why he sabotaged his opportunity to have sex with Rosie. On the long flight, he figures out that he would not be able to deal with the emotional consequences of having sex with Rosie, so he had subconsciously acted in a way that would sabotage the night. 

Other than asking how he is before the flight took off, Rosie leaves him alone. When they land in LA, he finally answers her, saying that he feels confused. On the flight to Melbourne, Rosie cries while watching the movie Bridges of Madison County. She asks Don if he cries at movies, and he says he doesn’t appear to be wired that way.

Back home, Don goes to dinner at Gene and Claudia’s on Sunday. They grill him about Rosie, and Claudia is happy to hear that Don will see Rosie again, even though he omits that it’s to run the DNA tests. At the university later, Gene catches Don reviewing the file on the Father Project, though Don lies and says it’s because he’s organizing a reunion as a favor to a friend. Gene reveals that he took the photo of Rosie’s mother’s graduating class that Don had used to determine the candidates; though Gene identifies Rosie’s mother by name—Bernadette O’Connor—he does not seem to realize that she is Rosie’s mom. He also tells Don that Geoffrey Case’s death was a suicide, attributing it to the fact that Geoffrey had bipolar disorder. When Gene briefly leaves the table, Don swabs his glass.