The novel follows Samantha Madison, a nearly seventeen-year-old who once saved the president of the United States from an assassination attempt. Despite being a national heroine, teen ambassador to the United Nations, and girlfriend of the president's son, David, Sam remains unpopular at her Washington, D.C., prep school, Adams Prep. She works part-time at Potomac Video to pay for art supplies, barely sees David due to their packed schedules, and feels overshadowed by her older sister Lucy, the most popular girl in school.
Seeking a fresh identity, Sam dyes her copper-red hair "Midnight Ebony" black. Lucy says she looks like Ashlee Simpson, the family's longtime housekeeper Theresa is alarmed, and Sam's twelve-year-old genius sister, Rebecca, compares her to a doodle of Joan of Arc. Undeterred, Sam heads downtown for a new art class at Susan Boone's studio, believing "life drawing" means sketching live people instead of fruit. She rides the Metro unrecognized for the first time, thrilled that her new hair has made her anonymous.
At the studio, David arrives with Rob, his ever-present Secret Service agent. Susan Boone introduces the class and calls the model, Terry, to the platform. When Terry drops his robe, Sam realizes with shock that "life drawing" means drawing nudes. She is the only person in the room who did not know. After the initial panic subsides, she breaks Terry's body into abstract lines and shadows and produces a passable drawing, though Susan critiques her for rendering Terry in isolation, floating on the page with no background. Sam is concentrating on the parts, Susan tells her, but ignoring the whole.
After class, David pulls Sam beneath the weeping willow tree in her front yard and invites her to spend Thanksgiving at Camp David, the presidential retreat in Maryland. He mentions horseback riding and "Parcheesi," and says he thinks they are "ready." Sam interprets the invitation as a proposal to have sex for the first time. With David's hand under her shirt, she whispers that she will come, then spends the following days in a spiral of anxiety.
Sam asks her parents for permission, expecting them to refuse. Her father agrees without hesitation, and her mother, distracted by a crisis involving Lucy's dismal SAT scores, barely registers the request. Sam confides in Lucy, who grasps the implication and responds with practical birth control advice, promising to buy condoms and spermicidal foam so Sam will not be recognized at a store. Lucy later leaves both on Sam's bed in a brown paper bag.
Sam begins avoiding David's calls, unable to decide whether she is ready. She agonizes over the double standard she sees at school: Girls rumored to have had sex are labeled sluts by Kris Parks, the varsity cheerleader, National Merit Scholar, and junior class president who founded Right Way, a student abstinence-and-values club. Meanwhile, Sam's coworker Dauntra, a politically outspoken woman, warns that the president's Return to Family initiative, a family-values program promoting shared family time, may have a hidden agenda. Sam dismisses the concern.
At home, Lucy's SAT troubles bring Harold Minsky, Sam's bespectacled, Hawaiian-shirt-wearing computer lab teaching assistant, into the household as a tutor. Harold is blunt, academically rigorous, and entirely unimpressed by Lucy's beauty, a novel experience for a girl accustomed to effortless male attention. Lucy grows fascinated, rents
Hellboy on Harold's recommendation, and asks Sam whether he has a girlfriend. She eventually reveals she has broken up with her longtime boyfriend, Jack, finding him controlling. She confesses she has fallen for Harold, who turned down her invitation to a movie. Sam advises Lucy to try again, suggesting Harold may simply be too shy to believe her interest is genuine.
At the second life drawing class, Susan Boone delivers a key lesson: A drawing is like building a house, and the artist must lay a foundation before hanging curtains. She sketches in the bench and room behind Terry to show Sam how to anchor the figure. After class, David mentions that his mother has already confirmed the Thanksgiving plans with Sam's mother, locking in the trip before Sam can reconsider.
Adams Prep hosts a televised MTV town hall meeting for the Return to Family initiative. During the broadcast, the president reveals a previously undisclosed provision: a bill requiring teens seeking prescription contraception to obtain parental consent, or requiring clinics to notify parents before providing such services. Sam, realizing this was never in the materials the White House gave her, interrupts the president on live television. Drawing on Susan Boone's lesson about parts and wholes, she argues that strengthening families requires balancing the rights of all members, not stripping teenagers of their privacy. In the heat of the argument, she blurts out that she has "said yes to sex," implying she has slept with the president's son, though she has not.
The aftermath is chaotic. The president threatens to send David to military school, but David defends Sam and points out that his father never disclosed the parental consent provision before asking Sam to promote the initiative. Sam's mother declares that both families should trust their children, and the first lady agrees. The Camp David invitation stands.
The next day at school, Kris Parks calls Sam a slut to her face and demands she drop out to protect Adams Prep's reputation. Lucy steps forward and publicly declares that if Sam is a slut, then she is one too, putting her own popularity on the line. She reveals she saw Kris in the limousine of Random Alvarez, the MTV VJ who hosted the town hall, undermining Kris's moral authority. Harold stands and announces "slut solidarity," followed by Catherine, Sam's loyal best friend, and then students across the cafeteria. Harold cites the school conduct code, and Kris is escorted to the principal's office, eventually losing her position as junior class president. Harold tells Lucy he cannot date her while he is her paid tutor but promises to take her out after she retakes the SATs.
At Camp David over Thanksgiving, Sam arrives determined to tell David she is not ready. After dinner and a movie, she waits in her room for him, but he never appears. She storms into his room and finds him reading a book on architecture. David reveals, with genuine confusion, that when he said "Parcheesi" and "ready," he literally meant the board game and spending a weekend with his parents. He never intended to propose sex. Mortified but moved, Sam runs back to her room, retrieves the brown bag Lucy gave her, and returns. They have sex for the first time, on Sam's own terms.
Back home, Sam's parents are cutting back work hours to spend more time with the family. Lucy reveals she is still a virgin and never slept with Jack; she bought Sam the birth control purely out of sisterly protectiveness. At Potomac Video, Dauntra praises Sam for standing up to the president and reveals she has hired a lawyer from the American Civil Liberties Union (ACLU) to challenge the store's backpack-search policy, inspired by Sam's example. Right Way has disbanded at school, and Kris has been stripped of her class presidency. At Susan Boone's class, Sam draws Terry again, this time integrating the figure into its background, building the drawing from the foundation up. Susan praises her improvement. Sam reflects that her relationship with David has not fundamentally changed after having sex; he still calls every night and morning. When David invites her to the White House the following weekend while his parents are away, Sam says she imagines her parents will say yes, quietly confident that she is learning to see the whole picture.