In a remote hilltop house, high school student Jill Johnson 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 insist that she "check the children," Jill begins to panic. Fear escalates to terror when she has the calls traced and learns that they are coming from inside the house. Jill must summon all of her inner strength if she is going to fight back and make it out of the house alive.