Katie (Lindsay Lohan) is young, lively, simple and lovely. Because of her parents' work, she grew up in Africa and received family education. At the same time, in that primitive and open place, Katie developed a strong character of forbearance. At the age of 15, Katie moved to Illinois with her parents and began her first school life in her life. But what was unpleasant was that Katie's relationship with her new classmates was not what she had imagined. The world of girls seemed calm and harmonious on the surface, but it was turbulent. In order to adapt to the new environment, Katie secretly learned the "rules of survival" and soon joined a very glamorous small circle in the school with her lovely appearance. Her gentle personality also seemed to win her a group of good friends. However, everything was calm, and it changed the moment she fell in love with the boy Aaron (Jonathan Bennett). It turned out that Aaron was the ex-boyfriend of Regina (Rachel McAdams), the most eye-catching girl in the school. Although they had broken up, the domineering and conceited Regina could not allow Katie to intervene. Thus, a war between girls quietly began. About friendship, about dignity, about sincerity, about trust. How will the girls learn and grow up?