Alvin Johnson (NICK CANNON) is a high school student who's good with cars but lousy with girls. He fantasizes about cheerleader Paris Morgan (CHRISTINA MILIAN), the most popular girl at his school, but he's all but invisible to her and her stuck-up friends Yvonne (NICHOLE ROBINSON) and Zoe (MELISSA SCHUMAN), except when jock Ted (AL THOMPSON) makes fun of him.
Thus, he seems relegated to hanging out with his fellow nerdy friends Walter (KENAN THOMPSON),
Kenneth (KAL PENN) and Chuck (KEVIN CHRISTY) and getting unwelcome sexual advice from his father, Clarence (STEVE HARVEY). His fortunes change, however, when he discovers that Paris has wrecked her mom's SUV and is in a bind for repairing it before she returns home.
Alvin then decides to offer to pay for the replacement part and do the labor himself in exchange for her posing as his girlfriend for two weeks so that he'll look popular and fit in with the in-crowd. She's naturally reluctant to this arrangement - not only because he's a nobody and she thinks all he wants is sex, but also due to her having a boyfriend, NBA player Dru (ELIMU NELSON) - but eventually agrees out of desperation.
When they then start acting like a couple at school, none of their friends can believe it. With some eventual coaching from her, Alvin then starts to adopt a cool, hip-hop demeanor and appearance, eventually making him quite popular with the other students. Yet, that comes at the expense of his former friends. From that point on and as Paris starts to fall for him, Alvin must decide whether to continue the charade or just be his former self.