The movie focuses on Matt Stifler, the younger brother of Steve Stifler
from the previous American Pie films. Matt is eager to enter the family business
of making films, so he can prove to his older brother that he is “up to the
standards of the Stifmeister.” Stifler and his friends play a prank on the band
students during the seniors’ graduation ceremony by spraying pepper spray on the
mouthpieces of the band’s instruments. Matt narrowly escapes getting caught and
stows the can of pepper spray in his front pocket, which subsequently leaks onto
his crotch. The band members begin to play “Pomp and Circumstance,” only to
become too irritated by the pepper spray to continue. During the commotion, one
of the students trips and pulls down the back curtain, which reveals Matt, who
is washing his pepper spray soaked genitals in a drinking fountain, in front of
the whole school.

Elyse demands that Stifler be punished for ruining their performance,
stating that he always gets away with his pranks because he is the school’s star
football player. The school’s guidance counselor Chuck Sherman (The Sherminator)
decides that a worthwhile punishment would be for Stifler to attend band camp,
in the hopes that he would make friends with the bandies and not follow in the
footsteps of his much-hated brother.

As Matt records the various happenings at the camp, he gradually becomes
friends with some of the band members from his school and even falls in love
with Elyse, who is revealed to have been a friend of Matt’s in 8th grade but had
a falling out after Matt started hanging around with Steve and his friends and
acting like The Stifmeister. Matt is eventually caught with his movies, and his
once-friends want nothing more to do with him...