Matt Stifler, the younger brother of Steve Stifler, is eager to enter the family business of making porn films so he can prove himself to his older brother. After Matt plays a prank on the school band, the school’s guidance counselor Chuck “The Sherminator” Sherman, who attended high school with Steve, decides that a worthwhile punishment would be for Matt to attend band camp. Matt is initially disgruntled by the idea but soon agrees to it, interested in the notorious sexual behavior of band camp girls (citing Jim’s marriage and sex life with Michelle as an example).
Upon arrival, Matt is extremely disrespectful to the rules along with everyone at Tall Oaks and even gets his school’s band in trouble. Jim’s dad, Noah Levenstein, the camp’s MACRO (Morale And Conflict Resolution Officer) recommends he start trying to fit in and earn the band’s trust. Matt conspires with his nerdy roommate, Ernie, to film the other band members in a bid called ‘Bandeez Gone Wild’, using hidden cameras.
During a lunch time scuffle Matt accepts a duel with rival band leader Brandon, wherein the performers show off their music skills, with Brandon playing the snare drum, and Matt playing the triangle. When it seems Matt has lost, he leaves the stage and comes back playing the bagpipes to the tune of “Play That Funky Music” to win the duel. Matt and Elyse later are attracted to each other and share a kiss while watching clouds in the sky. A Day before the finals the cheerleading group of East Great Falls arrive and catch Matt in band camp uniform and tease him by taking a photo and sharing it on the internet. Matt later offers a deal of showing them his film ‘Bandeez gone wild’ in exchange of deleting his uniform photo. While showing the girls his video a set of odd turn of events occur and Elyse sees the video hurt, she leaves.
The various school bands compete for points throughout camp with East Great Falls leading on the last day, but an ill-fated prank by Matt that was intended for the rival team, causes the band to lose and East Great Falls band member Elyse to lose a chance at a scholarship. Once the new term starts, Matt visits with Chuck, who reveals that he and the rest of Steve Stifler’s friends really couldn’t stand him, and begins to fix his mistakes by deleting the naked videos he took of others at band camp, and then persuades the school band to play Elyse’s piece to the Conservatory head, winning Elyse a scholarship (Brandon had been disqualified for plagiarism), and Matt her affection.