Sara Matthews (Minka Kelly) is starting her freshman year of college at ULA. Upon arrival, she meets Tracy Morgan (Aly Michalka), an avid party-goer, and Stephen Morterelli (Cam Gigandet), a drummer and fraternity brother who later begins to date Sara. After a party at Stephen's fraternity house, Sara arrives back at her dorm late at night and meets Rebecca Evans (Leighton Meester), her new roommate.
Initially, the girls begin to bond very well as Rebecca learns more about Sara's life. Sara had an older sister, Emily, who died when Sara was nine. She keeps a necklace that belonged to Emily as well as her sister's name tattooed on her chest. She also has an ex-boyfriend, Jason (Matt Lanter), who keeps calling her to try to get back together with her. As time goes on, Rebecca begins to become obsessed with spending time with Sara. She is willing to keep away anyone who wronged Sara or who she thinks is stealing Sara away from her. This becomes evident in multiple scenarios:
- It is implied, that the night they met, Rebecca was sitting in the dark waiting for Sara to come home.
– Tracy's avid party-going takes a turn for the worse when she invites Sara to a dance/bar club but leaves her there, who eventually calls Rebecca for a ride. Later, Rebecca attacks Tracy in the shower and threatens to kill her unless she stays away from Sara (she even rips Tracy's belly ring from her belly button). This leads Tracy, now fearing for her life, to move to another dorm.