Cady Heron is a hit with The Plastics, the A-list girl clique at her new school, until she makes the mistake of falling for Aaron Samuels, the ex-boyfriend of alpha Plastic Regina George.

Shelley is living a carefree life until a rival gets her tossed out of the Playboy Mansion. With nowhere to go, fate delivers her to the sorority girls from Zeta Alpha Zeta. Unless they can sign a new pledge class, the seven socially clueless women will lose their house to the scheming girls of Phi Iota Mu. In order to accomplish their goal, they need Shelley to teach them the ways of makeup and men; at the same time, Shelley needs some of what the Zetas have - a sense of individuality. The combination leads all the girls to learn how to stop pretending and start being themselves.