Beth Raymond (Shannyn Sossamon) is terrified by the deaths of four friends, three of which she personally witnessed, after they received chilling phone calls apparently from themselves in the future, showing the exact time of their deaths. After every death, a small red candy is found in the victim's mouth. In all the cases, the people who are going to die will see strange apparitions shortly before being killed, such as the woman seen on the theatrical poster with a baby carriage. Beth reports these strange occurrences to the police; however, they think she is delirious. Detective Jack Andrews (Edward Burns), believes her, stating that his sister died in a similar way. Together, they begin to unravel the mystery of the chain of calls, but are unsure if they can figure it out before Beth's phone starts to ring the same eerie tune.
They eventually trace the series of calls back to a woman named Marie Layton, who was apparently abusing her children, Ellie (Ariel Winter) and Laurel, for attention, as in cases of Munchausen by Proxy. They learn that Ellie later died of an asthma attack, and that Laurel is in a foster home after her mother went missing.
Believing that Marie is the source behind the murders, Beth travels to the recently burned-down St. Luke's hospital, where Marie was last seen, bringing Laurel in for a cut on her arm. After searching the hospital, Beth finds the body of Marie in the hospital ducting, where she apparently burned to death, clutching a cell phone. Marie's corpse moves and assaults Beth while weeping. She collapses when Detective Andrews makes his way into the ducting to help Beth. During this episode, the time of Beth's own phone call passes without her dying.
After contacting authorities, who arrive to collect the body, Beth returns home and Andrews goes to tell Laurel that her mother is dead. While visiting, Andrews sees a drawing that was drawn by Laurel on the wall. He realizes the drawing is a teddy bear and the baby carriage. Previously, it was shown as the jar with bugs and the baby carriage were in the area of where the nanny cam might be. He goes back to Laurel's room to get the teddy bear to see if there might be a nanny cam on the back. He finds a video disc in the back of Laurel's teddy bear. The disc is a video of a camera Marie hid in her children's room to monitor Laurel and Ellie. Ellie, clothed in a black hoodie, cuts Laurel's arm with a large butcher knife. Marie comes in and finds the children, realizing that the abuse she has been blamed for has been Ellie all along, and leaves to take Laurel to the hospital, locking Ellie in the bedroom.
Ellie, frantic, tries to force open the door, and suffers an asthma attack. Reaching for her inhaler, she finds it empty, and dies while dialing her mother's cell phone, making Marie the first real victim of the curse, dying in the fire. Laurel enters the room and Andrews says that it was Ellie who hurt her all the time, not her mother. Laurel nods, and speaking for the first time since the death of her mother, says, "But she always gave me candy," and holds out one of the red hard candies found in the mouths of all the victims.
The cellphone that Andrews gave Beth receives a voicemail, implying that Beth will soon be in danger again. Andrews realizes that the force behind the murders is Ellie, and races to Beth. Finding her unharmed, Andrews and Beth hear a knock on the door. Andrews looks through the spyhole. However, as Beth screams (as in her second voicemail message), a knife stabs through the spyhole and kills Andrews. After an explosion outside, Ellie's spirit appears and reaches out to strangle Beth. The spirit of Marie appears and grabs Ellie, saving Beth again. Marie's ghost vanishes, leaving Beth to stare bewildered into the distance. A red candy spills out of Andrews' mouth and his cell phone begins to dial a number on its own, revealing that Ellie's ghost is still out there, and more people will die.