Jill Johnson is a normal teenager. She has a boyfriend, she's a freshman in high school, a runner...But when she goes over her cell phone bill by 800 minutes her parents make her pay it off by baby sitting. She's driven to the Mandrakis' house, a rich family with 2 kids who are already asleep. but when the parents leave Jill starts getting weird calls. Somtimes the caller doesn't say anything, but when the ominous voice asks "have you checked the children?" Jill checks on them and returns only to have the caller phone again knowing she had gone upstairs. Jill freaks out and phones the police. They say they will trace the call if she can keep him on the line for more then a minute. But what the police tell her when she succeeds will turn a routine baby-sitting gig into a 16- year-old's worst nightmare. And now she has to fight for her-and the kids'- lives in a struggle for survival.