The sleepy Pacific Northwest town of Eureka is hiding a mysterious secret. The government has been relocating the world's geniuses and their families to this rustic town for years where innovation and chaos have lived hand in hand. U.S. Marshal Jack Carter stumbles upon this odd town after wrecking his car and becoming stranded there. When the denizens of the town unleash an unknown scientific creation, Carter jumps in to try to restore order and consequently learns of one of the country's best kept secrets.

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.

The kidnapping of a young girl propels her mother into a web of conspiracies.