In the vibrant city of Boston, young Clancy Finch finds herself ecstatic when her crush, Travis Schultz, invites her to a party at his home. However, her excitement is briefly overshadowed by a troubling incident involving her brother, Kevin, who is caught in a rather embarrassing moment dancing in the restroom by some older kids. These bullies record the amusing scene and torment him further, but their antics are swiftly put to an end by his protective mother, Margot, who is serving as a lunch monitor at the school. Not long after, their moment of humiliation turns into an unexpected viral sensation when the bullies upload a remix video of Kevin's dance moves alongside Margot’s fierce warning, shattering two million views on YouTube.
As the scene unfolds, things take a comedic twist when Kevin, Clancy, and their friend Mim are picked up from school by their father, Ron, a somewhat awkward yet lovable pastry chef. Eager to attend the party, Clancy pleads with her parents, but they both decline her request, leading to a moment of bitter words and her subsequent grounding. Later that night, Kevin's friend, Lewis, arrives for an exciting sleepover in the backyard which sets the stage for what’s about to unfold.
Under the cloak of night, Clancy and Mim decide to sneak out, which inadvertently leads to a hilarious encounter with the boys. While attempting to scare them away, Lewis finds himself making a hurried dash back inside only to stumble upon a shocking scene. Clancy's peaceful night soon spirals into chaos when he discovers two criminals breaking into their home. These intruders demand that Margot, who they mistakenly call "Matilda," come with them, holding Ron at gunpoint to ensure compliance. Classic parental obliviousness sees Ron completely out of his depth as Margot reluctantly agrees to go, removing her necklace as a token, much to Ron’s confusion.
Not fully believing Lewis’s outlandish story, Clancy, Mim, and Kevin venture back into the house where they encounter a U.S. Marshals agent, Henry Gibbs. Following a bit of a chaotic confrontation, they manage to tie him to a chair, only for him to divulge the startling truth: Margot has been living in the Witness Protection Program after turning in members of a dangerous crime syndicate, and now they’ve found her due to their newfound online infamy.
In a parallel storyline, we see the criminals, led by Elise and Margot's former fiancé, Leo Bouchot, meticulously plan their next move, all while unbeknownst to Margot who is caught up in her own situation. As things unravel, the kids cleverly decode Margot's hidden messages left in flour and her necklace, leading them to her clandestine spy center hidden away in a storage unit. Armed with a self-driving spy car, they attend Travis's party, only to face another ridiculous hurdle when they are stopped by the Coast Guard because of his revoked boating license.
The suspense intensifies as their quest leads them to an unexpected secret passage behind a painting, discovering their way to Margot's best friend, Jay who assists by tracking Margot’s GPS. Despite being told to stay put, Clancy takes matters into her own hands by handcuffing Jay to ensure they all leave together.
Their adventure culminates at a gala, where Margot, Ron, and Leo hatch a comical yet outrageous plan to steal the crown of the Queen of Moldana. Amid a series of slapstick blunders, Ron accidentally consumes a non-lethal poison intended for the Queen, causing chaos that leads to their detainment. However, Margot and Leo soon turn the tables, knocking out the security guards and reuniting with the kids, who infiltrated the gala disguised as a quartet.
The action-packed escapade reaches its peak at Leo’s safe house, revealing his deceitful intentions — he had never been in protective custody but rather the new head of the very syndicate they aimed to escape from. Facing a dangerous confrontation, they devise a plan to thwart Leo's lethal ambitions, leading to a hilarious series of events that ultimately sees Leo captured by the Boston Police.
As everything settles back to normalcy, Clancy receives a surprise visit from Travis, who returns her jacket, and Lewis’s mom arrives to pick him up, signaling the return to everyday life. In a tender moment, Margot permits Clancy to join the Berklee School of Music's summer program in Boston for cello, marking the end of their chaotic adventure with a sweet note of resolution.
