At a board meeting of the Wilderness Girls of America held in southern California, the strict and formidable Velda Plendor decides to vote against the Beverly Hills chapter, Troop 332, due to their continual underperformance. However, the compassionate leader of the organization, Frances Temple, presents the troop with a final opportunity by assigning them a new leader, Phyllis Nefler. Unbeknownst to them, Phyllis is a self-absorbed and extravagant shopper with an obsession for luxury, determined to spend her husband Fred into bankruptcy prior to their divorce. Their teenage daughter, Hannah (played by Jenny Lewis), is excited about having Phyllis as her troop leader, while Fred remains doubtful that Phyllis, who previously saved diligently to fund his thriving car muffler business, can shift her focus from shopping to camping.
Later, during a training session with Velda, Phyllis shows up in a lavish designer uniform, clearly ignoring the Wilderness Girls' principles of simplicity, which angers Velda and intensifies her mission to eliminate Troop Beverly Hills. The next day, Phyllis introduces herself to the new members of her affluent troop, including Hannah, Claire Sprantz (Ami Foster), Chica Barnfell (Carla Gugino), Tessa DiBlasio (Heather Hopper), Emily Coleman (Kelli Martin), Tiffany Honigman (Emily Schulman), and others, taking them to a campsite under the iconic Hollywood sign, all while traveling in limousines. When a rainstorm hits, she moves the troop to the Beverly Hills Hotel, where they bond over ghost stories by the fireplace.
The following day, Velda and her loyal sidekick Annie Herman (Mary Gross) confront Phyllis at the hotel, criticizing her for tarnishing the organization's reputation. Even after Velda dismisses Phyllis, she persists in attending the Annual Wilderness Craft Day convention, leading her troop in a fashion show that ultimately ends in ridicule. Meanwhile, with Velda's covert surveillance of the troop carrying on, Phyllis strives to restore the girls' morale and teaches them how to thrive in their own "wilderness" of Beverly Hills. This includes indulgences such as spa days, diamond appraisal lessons, CPR training from a charming police officer, and entertainment visits to a retirement home.
Eventually, Phyllis takes her troop to her divorce hearing to expose them to legal realities, where she is heartbroken to discover Fred’s intentions of remarrying. Nonetheless, she later triumphantly announces that the girls have earned an impressive 36 patches in a short span of three weeks, planning a celebratory event aboard a glamorous yacht. During the celebration, Hannah receives her unique "Sushi Appreciation" patch amidst her parents, but when she attempts to prompt them into a reconciliation kiss, Fred's new fiancée Lisa ends up tumbling off the yacht.
As Velda prepares to dismiss Troop Beverly Hills by showcasing incriminating evidence through photographs captured by Annie, there’s a shift in perspective. Frances realizes that despite Phyllis's unconventional methods, she has actually fostered a sense of community and personal growth within the girls, showcasing their abilities to navigate their lives effectively. However, Velda is relentless and orders Annie to live with the Neflers to gather more dirt. Interestingly, Annie witnesses only Phyllis’s goodwill.
In a turn of fate, the troop must sell 1,000 boxes of cookies to qualify for an upcoming jamboree while Velda attempts to sabotage them by selling cookies in their territory. Disheartened, Annie chooses to aid Phyllis and offers her insider knowledge to ensure the troop's success. Through a newfound understanding of community values, Phyllis teaches her troop meaningful approaches to selling cookies, which results in an astounding sales record of 4,732 boxes—enough to qualify for the jamboree.
In celebration, Phyllis invites Velda to a formal gala, during which Fred unexpectedly praises his wife for her dedication and acknowledges her transformation back to the woman he once loved. Yet, he surprises her by requesting joint custody of Hannah instead of rekindling their marriage. Consequently, a distraught Phyllis finds herself in the pool, spiraling into resignation from her troop leadership when she is met with steadfast resistance from her girls, who view her as an inspirational figure.
Encouraged by both the girls and Fred, Phyllis rediscovers her commitment, ready to lead them into the jamboree. Arriving in style at the campsite, they are determined to outshine the Culver City girls. However, they face sabotage from their competitors, leading to a chaotic series of events. Ultimately, when the bridge collapses under Velda’s leadership during the final challenge, Phyllis’s resourcefulness shines through as she and Hannah work together to navigate the obstacle.
Despite the Culver City team racing ahead, they become disqualified due to Velda’s absence. Troop Beverly Hills emerges victorious, claiming the championship trophy. As Velda faces the consequences of her actions, the victory leads to a heartwarming reunion between Phyllis and Fred, solidifying their hopes for a renewed relationship.
In the following year, Troop Beverly Hills gets the honor of being the Poster Troop, while Velda faces the ramifications of her previous behaviors, forced to find new employment at Kmart.
