A homeschooled teenager attends public school for the first time and finds herself embedded with a group of popular girls in an attempt to bring down the hateful clique as planned by two of her new outcast friends.
Cady's parents get her ready for her first day at school and later she gets into a fight with Janis Ian out front during her party.
Cady arrives for her first day of school and soon ends up hanging out with two outcasts, Janis Ian & Damian, in the field behind the school.
Cady hides out in the bathroom to eat her lunch on her first day, and later she walks down the hallway with Janis Ian and Damian while learning about the school.
Cady is pulled out of health class to talk to the principal and then all of the female students are brought in by the principal. Later, the students attend the Spring Fling set up in the gym.
Cady goes with the Plastics to the mall and sees Janis Ian working there.
The Plastics head to Regina's house to hang out.
Regina complains to her boyfriend about Cady while driving to her party. She learns the depth of Cady's deception when she gets back to her parked car.
Regina tells Principal Duvall about the Burn Book and he interrogates Cady and the other two about it.
Cady attends the Mathletes State Championship that she wins in the sudden death round.