David Auburn

Catherine confronts Hal after discovering he has taken a notebook belonging to her deceased father. The confrontation escalates as Catherine accuses him of theft, but Hal reveals the notebook contains a poignant entry about her, written by her father.

Catherine's estranged father, Robert, appears on her 25th birthday, bringing champagne. Their conversation quickly turns from lighthearted banter to a tense discussion about Catherine's mental state and her fear of inheriting her father's genius and madness.

Catherine and Hal are outside a raucous funeral reception for Catherine's father, a brilliant mathematician. Hal tries to comfort Catherine and connect with her, leading to a discussion about the pressures on mathematicians and the story of a female mathematician who had to hide her identity.