Sara, a bright and sociable college freshman, arrives at the University of Los Angeles and quickly becomes friends with her new roommate, Rebecca. Initially, Rebecca appears supportive and friendly, helping Sara adjust to campus life and introducing her to new friends. As they grow closer, Sara starts noticing peculiar traits about Rebecca's behavior, such as an intense clinginess and a disturbing fascination with her life and friends.

As time progresses, Rebecca's actions become increasingly invasive and alarming, causing Sara to feel uneasy and trapped. The turning point comes when Sara realizes that Rebecca's obsession is far more sinister than she initially perceived, putting her relationships and personal safety at risk. Struggling to maintain her sanity, Sara faces a chilling challenge to extricate herself from Rebecca's escalating fixation.