New student Cady Heron finds herself in an elite group of popular girls, led by the cunning queen bee Regina George and her sidekicks Gretchen and Karen. However, when Cady makes a serious mistake by falling in love with Regina's ex-boyfriend Aaron Samuels, she becomes the target of Regina's wrath. With the help of her outcast friends Janis and Damian, Cady plans to take down the group's main predator, but in doing so, she must learn to stay true to herself and navigate the cruel high school jungle.