On prom night, Julie (Kathryn Newton) confides in her closest friends Kayla (Geraldine Viswanathan) and Sam (Gideon Adlon) about her plan to lose her virginity to her boyfriend Austin (Graham Phillips). Inspired by this revelation, Kayla vows to follow suit but intends to do so in a more casual manner with her lab partner, Connor (Miles Robbins). Meanwhile, Sam is grappling with her identity as a closeted lesbian and, despite her hesitations, decides to join the pact in hopes of solidifying her bond with her friends before they all head off to college. She attends prom alongside the quirky Chad (Jimmy Bellinger), who wears a fedora and is pretty harmless.
Lisa (Leslie Mann), Julie's mother, hosts a pre-party for both parents and kids, adding a layer of tension as Julie conceals her acceptance to UCLA from her mother, who disapproves of the choice. Upon Julie's departure, Lisa discovers the acceptance letter hidden in her daughter's room.
Meanwhile, Mitchell (John Cena), Kayla's father, tries to reconnect with Lisa after her earlier evasions, while Hunter (Ike Barinholtz), Sam's free-spirited father who divorced due to his infidelities, arrives in a limousine to whisk the girls away, promising to make their night unforgettable. As the evening unfolds, the girls text each other about their pact, inadvertently allowing Mitchell and Lisa to stumble upon their messages when they overhear Julie's open laptop. Enlisting Hunter's help to decode the emoji-laden texts, the group realizes they must intervene to prevent the girls from following through with their plans.
As the parents tail the girls from one party to the next, it's evident that underlying issues fuel their overprotective behavior. Mitchell is in deep denial regarding Sam's sexuality and believes she requires protection from boys like Connor. Hunter, burdened by guilt for neglecting Sam following his turbulent split from her mother Marcie (Sarayu Rao), keeps insisting on looking after her. Lisa, grappling with her own insecurities about letting Julie grow up and leave, feels that UCLA is too far, preferring she attend the University of Chicago instead.
The night culminates in a heated argument between Lisa and Julie after a drunken Sam decides against sleeping with Chad, who prematurely ejaculates. Kayla also reevaluates her casual stance on virginity while she and Connor opt to get to know each other better. When Mitchell bursts into the scene and aggressively confronts Connor, Kayla recognizes her father’s genuine intentions, appreciating his guidance in matters of self-protection.
As the night progresses, Sam shares a heartfelt moment with Hunter, where they bridge the gap of neglect. Sam comes out to her father, marking a significant step in their relationship, while Lisa is touched by the evident love shared between Julie and Austin. She makes a discreet exit from their hotel room, granting them the privacy they desire.
In a poignant moment, Lisa resolves to maintain her friendship with Mitchell and acknowledges Hunter’s struggles of being ostracized. The bond strengthens as the three girls swap stories, with Sam openly coming out to Julie and Kayla, both of whom offer unwavering support. In a romantic twist, Sam shares a kiss with her crush, Angelica (Ramona Young).
Fast forward three months, Julie embarks on her college journey with Sam and Kayla accompanying her to California. As they drive away, Lisa discovers she has been looped into their group chat, which teems with plans for drugs. The three parents rush to the car but quickly learn that the girls were just having a bit of fun, culminating in a light-hearted "I love you" text sent back to them.
