Scout Bozell has always dreamed of joining the safety patrol at Rockridge Middle School, but his clumsy, hazardous nature keeps tripping him up at every turn. In the film’s opening, a sequence begins with him examining a banana peel, a chain of mishaps unfolds: a kid trips over his backpack, marbles roll out and send other kids sliding, a girl’s lunchbox goes airborne and clocks the principal, and as Scout Bozell swipes at the peel to toss it away, he accidentally knocks a kid off his bike. This chaotic cascade culminates in a plastic squirrel that the bike collides with, which then smashes into a truck loaded with giant frozen tuna—causing a dangerous slide on the road that ends with the last member of the safety patrol, Joe Lobes Lobenick, being devoured in a grotesque, traumatic moment and wiping the patrol from the roster until he recovers.
The faculty tries to fix the mess by convincing Principal Tromp to bring Scout Bozell onto the safety patrol. The plan works, but only after boundaries are redrawn, moving Scout to Laurelview Middle School, a campus wrestling with a far larger problem: petty theft carried out by two staff members, the lunchlady Mrs. Day and the janitor Mr. Miller. They collaborate with the safety patrol’s own, bullying-tinged unit led by Kent Marlowe, the principal’s son, Kent Marlowe. The new environment is tense and suspicious, and Scout’s arrival quickly becomes the flashpoint for a larger conspiracy.
At Laurelview, the opening safety-patrol ceremony sees Scout cheerfully declare, “Go safeties!”—a rallying cry that resonates with some and inflames others, particularly the rival group led by Kent. There, Scout befriends a kid named T'Boo, who introduces him to Lefty (who is right-handed), Red, Walt Whitman, Lucky, and Hannah Zapruder, one of the school’s cheerleaders. It’s revealed that T'Boo has a fear of frogs after a biology class incident in which a frog seemed to come back from the dead. The situation grows more personal when Scout’s grandfather—Grandpa Bozell—suffers several injuries (including a broken jaw) after Scout unknowingly knocks him off a ladder, adding emotional weight to the already precarious balance of school life.
When Mrs. Marlowe learns that a safety-patrol member is connected to the thefts, Kent, Mrs. Day, and Mr. Miller search for a scapegoat and plant the key to Mrs. Marlowe’s office and a lighter on Scout. During a ceremony, Hannah is named valedictorian, and the planted evidence looks like a convergence of guilt for Scout. Later, when fellow patrolman Coop asks Scout to fetch his gloves, Scout discovers that the office fire is burning, and he extinguishes it while saving a hamster. Yet the key and lighter fall from his pocket, making it seem that Scout stole them and started the blaze, and he is expelled from the safety patrol and barred from the Fall Ball.
Hannah and her friends soon realize Scout was set up. A pivotal moment comes when Hannah’s father searches through his tapes for something to send to Wink Martindale, and they watch the ceremony together, discovering Kent, Mr. Miller, and Mrs. Day planting the incriminating items on Scout. With this new evidence, Scout, Hannah, T'Boo, Red, Walt Whitman, Lucky, and Lefty uncover the true culprits: Mr. Miller and Mrs. Day as the Bartletts, Georgina and Tim Bartlett, rather than innocent staff members.
The group head to the Fall Ball and present their findings to the audience, enlisting the help of a celebrity appearance and tape to reveal the truth: Weird Al Yankovic performs a scene that exposes Kent and his gang. The Bartletts attempt to rob a tent, taking Hannah hostage aboard Weird Al’s hot-air balloon. Scout Bozell pursues them, and Hannah hurls a sack of money over the edge to coerce Georgina to land the balloon. Tim chooses to jump, hanging onto the edge, while Scout dives to save him but ends up in a small patch of water. To force Georgina’s safety, Hannah dangles more money overboard, causing Georgina to land the balloon—though she slips and falls into a hollow. Scout and his friends rescue her from a deadly fall, and, in a touching shift, T'Boo encounters a frog but seems to move past the fear.
With the Bartletts apprehended, Scout is reinstated on the safety patrol and ultimately named captain by his personal hero, John Walsh. The hierarchy within the patrol changes: Kent and his crew are replaced by T'Boo, Hannah Zapruder, Red, Walt Whitman, Lucky, and Lefty. Grandpa Bozell makes a full recovery, though soon afterward is knocked out when a waxer—previously appearing harmless—seems to come to life after being plugged in by Scout. And in a final note of mischief, Mr. Zapruder appears to capture the moment on tape to send to Wink Martindale, but his camera ends up with no tape in it, leaving the scene unresolved yet fundamentally triumphant for Scout and his friends.
