The film begins with Mark, a mechanic in his late 30s, finally giving in to his friends' nagging to try online dating. After creating a profile, he matches with a woman named Emily, who seems perfect in every way - beautiful, intelligent, and with a sense of humor that matches his own.
As Mark and Emily begin to communicate online, he starts to feel excited about the potential for a real connection. They arrange to meet for a date at a local café, and Mark is instantly smitten with Emily's charm and personality.
However, as their relationship progresses, Mark starts to notice strange behaviors from Emily. She begins to show up unannounced at his workplace, leaves excessive voicemails and text messages, and becomes possessive of his time.
At first, Mark brushes off Emily's behavior as just being overly enthusiastic about their relationship. But as her actions become more and more erratic, he begins to feel afraid and trapped by her obsessive behavior.
One night, Mark receives a chilling message from Emily, confessing her love for him and threatening to harm anyone who gets in the way of their relationship. Terrified, Mark decides to end things with Emily and block her from all forms of contact.
However, Emily's obsession with Mark only intensifies in the wake of their breakup. She begins stalking him, showing up at his home uninvited and even sabotaging his car in an attempt to prevent him from leaving her.
Desperate and fearing for his safety, Mark confides in his friends and the police about Emily's increasingly dangerous behavior. But as they investigate, they discover a dark and twisted past to Emily's obsession with Mark - one that could have deadly consequences.
As the tension between Mark and Emily reaches its breaking point, Mark must confront the terrifying reality that he may be facing a killer in the guise of a lover. Will he be able to escape Emily's deadly grip before it's too late, or will he become her next victim in this twisted tale of obsession and murder?