Growing up shy and unpopular, Charlene never had many friends. That is, until she meet Sarah, a beautiful and charismatic American-French girl who moved back to Paris for high school. Much to Charlene's shock and delight, the two girls quickly develop an intense friendship. With Sarah by her side, Charlene finally begins to feel accepted and even loved. However, after a brief idyllic period, the girls' relationship becomes rocky and friendship veers towards obsession. As Sarah drops Charlene for older, more glamorous friends, Charlene's devotion spirals into hatred.