Buffalo Grove High School valedictorian Denis Cooverman (Paul Rust) has had quite an academic career... on paper, at least. Superlative student, conscientious young gentleman and patently obvious dork, Denis has played it safe and made it all the way to graduation day without ever having really experienced some of the joys of higher learning: breaking curfew, destruction of property, over-consumption of alcohol, fist fights, late nights, fast cars or faster women (actually, women of any sort).
But all of that is about to change, and all by uttering five little words: "I Love You, Beth Cooper."
Seems that Denis has been harboring a secret for six years, a chronic case of l'amour fou for Beth (Hayden Panettiere), one of the most popular girls in school, who sat in the desk just in front of him in multiple classes (God bless alphabetical order!). And thanks to his colorful best friend, Rich (Jack T. Carpenter), Denis has been goaded into telling the truth and declaring his love during his valedictory address - while also putting names to several other white elephants stampeding through the senior class.
His resulting embarrassment is short-lived, however, when The Trinity - Beth and her two best friends, super-bitchy Cammy (Lauren London) and super-easy Treece (Lauren Storm) - shows up to his and Rich's ad hoc graduation night party. Unfortunately for Denis, Beth's thick-necked, military hopeful boyfriend, Kevin (Shawn Roberts), also shows up, with two equally menacing, double-digit IQ friends in tow. When the inevitable can of "you insulted my woman!" whoop-ass is opened, Beth comes to the rescue, and whisks Denis, Rich, Cammy and Treece away in her beat-up Cabriolet.
As the chase continues from sunset to sun up, Denis realizes that his little speech has given rise to one of the wildest, most eventful, most hilarious and most revealing nights of his life.