Chris and his girlfriend Rose go upstate to visit her parents for the weekend. At first, Chris reads the family's overly accommodating behavior as nervous attempts to deal with their daughter's interracial relationship, but as the weekend progresses, a series of increasingly disturbing discoveries lead him to a truth that he never could have imagined.
When Erik Stifler realizes that he's the only Stifler family member who might graduate high school a virgin, he decides to live up to his legacy. After some well-meaning advice from Jim's dad, Erik's ready to take his chances at the annual and infamous Naked Mile race, where his devoted friends and some uninhibited sorority girls will create the most outrageous weekend ever.
Erik, Ryan, and Cooze start college and pledge the Beta House fraternity, presided over by none other than legendary Dwight Stifler. But chaos ensues when a fraternity of geeks threatens to stop the debauchery and the Betas have to make a stand for their right to party.
