Summary
A montage shows Karen, Regina, Gretchen, Janis, and Damian primping for the Spring Fling dance, while Cady dons her Mathletes uniform to go to the Illinois High School Mathletes State Championship. Ms. Norbury wishes the team luck against Marymount High School, and Cady frets in the first round about whether she is smart enough. Back at Cady's house, her mother asks her father where Cady is, since she's grounded. The puzzled dad responds, "Are they not allowed out when they're grounded?" The parents go looking for Cady at the Spring Fling, not knowing she chose to go to the Mathletes championship instead.
At the end of the last round, North Shore High School is tied with Marymount, and the match goes into a "sudden death" round between one representative of each team, chosen by the opposing side. Both teams choose the female members—Cady from North Shore, and a dowdy girl named Caroline from Marymount. As the judge reads the final question, Cady realizes that criticizing Caroline's looks won't help her win the competition, and is disheartened when Caroline buzzes in first. However, Caroline's answer is incorrect, and Cady manages to provide the right answer and win the title for the North Shore Mathletes. Ms. Norbury and the crowd celebrate, and Kevin Gnapoor rips his shirt open in jubilation.
Outside the venue after the competition, the team tries on their championship jackets. Although Cady is reluctant to push her luck while she's grounded, Kevin and Ms. Norbury convince her to go to the Spring Fling anyway. Cady shows up just as Mr. Duvall begins his speech announcing the winners for Spring Fling king and queen. Cady wanders through the crowd and spots her parents near the bleachers as Mr. Duvall crowns Shane Oman as Spring Fling King, and is in the middle of walking over to them when she hears her own name called as Spring Fling queen.
The crowd applauds politely and then is silent as Cady takes the stage and dons her tiara. Speaking into the microphone, Cady admits that half the people in the room dislike her, and apologizes to the people whose feelings were hurt by the burn book. Cady observes that "everybody looks like royalty" at the Spring Fling, and breaks the Spring Fling tiara apart, saying that everyone should share it (and causing Damian to gasp). She tosses a piece to Gretchen, a piece to Janis, and a piece to Regina, before tossing the rest of the sparkling tiara pieces into the audience.
Later, Cady runs into Janis and Damian, who are wearing matching purple tuxedos. They reach a truce, and Damian alerts Cady to Aaron Samuels standing nearby. Aaron presents Cady with two gift certificates, one of which Janis and Damian promptly steal, and wishes her congratulations on winning the Mathletes championship. They begin to dance, and a tracking shot shows Cady and Aaron, Regina and Shane, Ms. Norbury and Mr. Duvall, and Janis and Damian all locked in an embrace on the dance floor. Janis and Damian awkwardly attempt to kiss before both recoil in disgust, and Kevin Gnapoor swoops in to take Janis's arm.
In voice-over narration, Cady explains that The Plastics broke up after a therapist successfully managed to get Regina to channel all her aggression into playing lacrosse. Karen began doing the morning weather announcements, and Gretchen switched to hanging out with a different clique. Aaron attended Northwestern University in Evanston, where Cady can still see him. "Girl World," Cady recalls, "was at peace."
On the front lawn of the school, Damian spots a group of freshmen girls he jokingly calls the "Junior Plastics" and Cady jokingly implies that if any girls try to disturb the peace, she'll simply ram them with a schoolbus, before the film ends.
Analysis
Although Ms. Norbury obligates Cady to participate in the Mathletes championship, Cady's acquiescence in doing so symbolizes the fact that she is finally embracing the parts of her identity that she previously felt compelled to conceal in the film, for fear of "social suicide." Cady's realization when competing in the "sudden death" round is essentially a repudiation of the values and rules of "Girl World." Cady acknowledges that, when trying to achieve one's goals, petty insults and emotional manipulation will never be a satisfactory replacement for hard work and commitment. Cady's winning answer at the Mathletes championship—"The limit does not exist"—might also refer in a figurative sense to the liberation of her identity from the suffocating constraints of "Girl World."
Both Ms. Norbury and Kevin Gnapoor encourage Cady to go to the Spring Fling, although Cady no longer feels she has anything to prove in the social sphere. When Cady unexpectedly wins Spring Fling queen, her decision to physically shatter the tiara and distribute it reflects the destruction of the rigid hierarchy that has until then kept the North Shore High School under its tyrannical grasp. Rather than lord over the school as a member of an elite group of "royalty" led by a "queen bee," Cady forsakes her own queendom and in doing so, tries to encourage a more egalitarian social dynamic among the students.
At the end of the film, Janis and Damian emerge as the film's most stable, durable example of virtuous friendship—never betraying, manipulating, or lying to one another. Their decision to wear matching purple tuxedos to the Spring Fling represents their close companionship as well as their shared iconoclastic attitude. Their failed kiss on the dance floor hints at the fact that both characters are under considerable pressure from society to perform as if they are a straight couple, even though they are both likely gay.
The Spring Fling is the third seasonal event of the film (after the Halloween party and the Winter Talent Show), marking the culmination of the film's school-year-long plot. In an epilogue, Cady reveals the fate of The Plastics to the audience in voice-over narration. Much in the way that Cady embraced math when she stopped worrying about "Girl World," Cady recalls that Regina later discovered her natural lacrosse ability, suggesting that the complex, emotionally draining rules of their social lives were indeed limiting the girls from reaching their fullest potential.
After reckoning with the animalistic chaos unleashed by the Burn Book, Cady remarks at the end of the film that "Girl World" was finally at "peace." When she and Damian spot a group of freshmen girls who resemble The Plastics (Damian calls them "junior Plastics"), Cady darkly jokes that she now knows how to "deal with them," fantasizing about them getting hit by a bus. Although meant as a joke, Cady's last line echoes Regina's accident and Cady's close call, and reinforces the theme that even without The Plastics, high school remains a savage and treacherous domain.
