Cady soon learns about the "Burn Book", a scrapbook the Plastics have made that is filled with horrible rumors, secrets, and insults about other girls and some teachers at school. Using the book, Janis devises a plan to get back at Regina but Cady is reluctant, thinking Regina is a good friend. Cady fell in love with Regina's ex-boyfriend, Aaron Samuels, and purposely fails math, a subject she is gifted at, in order to have an excuse to talk to him. Regina finds out about Cady's love for Aaron and jealously steals him back at a Halloween party by kissing him in front of Cady. This spurs Cady to fully commit to Janis' plan to cut off Regina's "resources": involving breaking Regina and Aaron up, tricking Regina into eating "Swedish nutrition bars" that actually make her gain weight, and turning Regina's fellow Plastics against her. In the process, Cady unwittingly remakes herself in Regina's image, becoming spiteful and superficial, and abandons Janis and Damian.