While cleaning up after her party, Margo receives a call from her sister, Maureen, who confesses to creating the previous year’s list. Maureen explains that she found the official Mount Washington embossing stamp in her locker, named Rachel prettiest junior and herself prettiest senior, and named Jennifer ugliest. After graduation, Maureen told Jennifer what she’d done, threw the stamp in the trash in front of her, and declared the tradition over. Margo realizes that Jennifer must have retrieved the stamp and created this year’s list.

Margo immediately drives to Jennifer’s house and confronts her. Jennifer admits everything, explaining that she put herself on the list because it makes her “somebody” and that she named Margo prettiest. She also confesses to having read Margo’s diary back in eighth grade to understand why their friendship was ending, using the information to undermine Margo’s confidence. Jennifer agrees to give Margo the stamp only after the dance, threatening to hand it off to someone she has already chosen for next year if Margo exposes her. She warns that telling would put Maureen at risk too. To end the tradition for good, Margo agrees to keep Jennifer’s secret for the night.

Grounded from homecoming, Abby receives texts from Lisa about the football team’s loss. Frustrated and bored, Abby does her hair and makeup as if she were going to the dance. Fern attempts to tutor her in Earth Science, which quickly escalates into an argument. Abby accuses Fern of being jealous because Abby is pretty and Fern is ugly. In tears, Fern reveals that she was on last year’s list as the ugliest sophomore. Abby is stunned, finally understanding the source of Fern’s past misery. The sisters reconcile; Abby insists that Fern isn’t ugly, and Fern insists that Abby isn’t stupid. Fern says that she will stay home rather than go out, but Abby tells her she should go. Abby offers to do her makeup, an offer that Fern declines before they part on better terms.

Lauren returns from the football game feeling ecstatic. Her mood sours when she finds her mother waiting in the kitchen with the copy of the list she discovered in Lauren’s bag. Mrs. Finn declares that she’s quitting her job, selling their house, and pulling Lauren out of Mount Washington High. She also forbids Lauren from attending the homecoming dance. Distraught, Lauren goes to her room. After her mother leaves, Lauren puts on a long, black dress; climbs out her bedroom window; and runs barefoot toward the pre-homecoming party.

Bridget nervously prepares to try on her red homecoming dress. She tries to make peace with Lisa, who’s getting ready in the bathroom, but Lisa angrily rejects her and slams the door. In her room, Bridget puts on the dress and is relieved that it fits. When she lifts her arms in celebration, however, the dress sags, revealing that it’s now too big. Thrilled with this evidence of her weight loss, she uses safety pins to make the dress tighter. Her triumph is cut short when her stomach growls, filling her with self-disgust. Convinced that she will never be pretty enough, she finishes getting ready without looking in the mirror.

At her pre-homecoming party, Candace’s mother applies heavy, mask-like makeup to her face. Lauren arrives, revealing that she snuck out after her mother announced that she was pulling her from school. Lauren proceeds to get very drunk and is openly mocked by the other girls. Candace walks with the intoxicated Lauren to the school. Upon arrival, Lauren becomes sick. The other girls leave them and head into the dance. Instead of joining them, Candace decides to stay and care for Lauren. She resolves to walk Lauren home and begins wiping off her own heavy makeup.

In her bedroom, Sarah resists putting on the foul-smelling clothes she wore all week as part of her protest. Milo arrives with a corsage of white daisies. He tells her that he can’t make her feel beautiful; she must believe it herself. He gently coaxes her into taking a shower. Afterward, Sarah emerges clean and changes into a fresh T-shirt and jeans before putting on the corsage. They walk to the school, but Sarah refuses to enter the dance, feeling like she has failed in her protest. Instead, they sit on their bench outside. Sarah confesses to Milo that she doesn’t think she has ever truly felt beautiful, and he holds her as she allows herself a rare moment of vulnerability.

At the homecoming dance, Jennifer carries the Mount Washington embossing stamp in her clutch while campaigning for homecoming queen, much to the apparent surprise of Rachel and Dana. As she dances, she reflects on her private motivations for placing each of the other girls on the list. She has a brief, awkward conversation with Bridget, who tells her that the list has made her life worse. Later, Principal Colby finds Jennifer on the bleachers and privately informs her that she hasn’t won the election. The principal advises Jennifer that this is an opportunity to decide how people will see her. The news devastates Jennifer.

Principal Colby takes the microphone and announces Margo Gable as homecoming queen. As the crowd searches for Jennifer, the principal quietly informs Margo that Jennifer has already left the dance. This news worries Margo, who fears that Jennifer will now refuse to hand over the embossing stamp. Margo pushes the thought aside, deciding to enjoy her victory and deal with the stamp later. As Principal Colby places the tiara on her head, Margo is surprised by its weight and realizes that her long-coveted crown is made of cheap plastic, not metal.