Nicole Walker (Reese Witherspoon) has always wanted a boyfriend who is strong, sexy, and sensitive, and she seems to have found it all in David (Mark Wahlberg). However, not long into their relationship, she realises that his perfect exterior hides a dark and violent nature, and tries to break contact with him. David then begins stalking her, terrorizing her, and along with his wrong-side-of-the-tracks buddies, eventually lays seige to her house.