Alex, a college sophomore at Georgetown University, is told by her mother over the phone that she and her younger brother have an older half sister, a child from her father's previous relationship before marrying her mother. Her older half sister, Penelope, is from France and lives in New York City after attending NYU. Her mom says Penelope will visit DC and wants to meet her.

At first Alex is upset her dad didn't tell her, but she likes the idea of having a glamorous sister. She forgives her parents more easily than her brother, who plans to refuse to meet Penelope.

Alex has stopped drinking and partying in excess this year of college after a wild first year. Her friends are mean to her about it except her roommate--because her roommate is dorky and Alex is her only friend and because her roommate knows what happened to Alex one night the previous year when she was incredibly drunk and two or three boys raped her in a room at a party and she barely remembered. One of the boys she had had sex with earlier that year.

Alex hasn't told anyone else, for fear of humiliation and social ostracization and burning bridges and the draining process of having to tell her story again and again.

Alex goes to a therapist at the school who says she should tell her RA and asks her to make an appointment for the next week, which Alex makes then cancels.

She calls Penelope after receiving a voicemail from her and her voice breaks on the phone. Sensing something is wrong, Penelope asks if she should come and takes the train that night, arriving at 2 am. They go to a diner to talk. Alex tells Penelope the story. Penelope says something similar happened to one of her friends at NYU. Alex says the therapist told her to talk to her RA but she doesn't want to. Penelope asks if she's too embarrassed, which Alex says she is. Penelope asks if she's talked to her boyfriend. Alex says she doesn't have one. She says Alex could or couldn't talk to her RA, and it depends how much she's "prepared to get [her]self into." Alex asks what Penelope would do. Penelope says she'd probably confront the boys directly but be too afraid to talk to her RA or dean. Alex finds herself let down and disappointed. She had wanted Penelope to command her to do the thing she was scared to do and "set things in motion." Penelope offers to go with Alex to the RA. Alex blames herself. Penelope tells her not to. Outside the diner, Alex cries and her sister hugs her and holds her hand.