The movie begins Jordan Turner, who is a veteran 9-1-1 operator at the Los Angeles Police Department. One Night, she receives a call from Leah, a teenage girl whose life is in danger as a man has forcefully entered her house and is trying to kill her. She cries to Jordon for help, who tries to calm her down and ask to lock herself in a room upstairs. Leah hides in a room as directed by Jordon and her phone suddenly disconnects. Jordon gets worried and calls Leah back.
But this turns out to be the worst decision of Jordon as Leah’s ringtone directs the killer to the victim and Leah is killed. As her call leads to death of Leah, Jordon is left with guilt. Six months later, she receives another call at night, where a teenage girl Casey is abducted by a man, and she cries for help to Jordon. She realizes that the killer is the same person who killed Leah and decides to stop him from killing his another victim.