In a remote hilltop house, high school student JILL JOHNSON (Camilla Belle) settles in for a routine night of babysitting. With the children sound asleep and a beautiful home to explore, she locks the door and sets the alarm. But when a series of eerie phone calls from a STRANGER insists that she "check the children," Jill begins to panic. Fear escalates to terror when she has the calls traced and learns that the calls are coming from inside the house. Jill must use all her strength if she is going to fight back and make it out of the house alive.