Jill Johnson (Carol Kane) is babysitting the chlidren of Dr. Mandrakis (Carmen Argenziano) at their home. When the chlidren are asleep, Jill receives a telephone call from a man who asks her if she has checked the chlidren. At first, Jill dismissess the telephone calls as a practical joke. However, as the calls become more frequent and threatening, Jill becomes frightened and decides to call the police, who promise to trace the caller if Jill keeps him on the telephone line long enough. Jill, frightened to extreme measures, arms herself as she receives one final cal from the nefarious stalker. Soon after the converstion, Jill receives a call from the police, only to find out that the stalker is calling from inside the house. A light comes on at the top of the staircase, and Jill sees the s