| Director | Fred Walton |
|---|---|
| Budget | $1.5 million |
| Box office | $21.4 million |
Teenage babysitter Jill Johnson arrives at the home of Dr. Mandrakis and his wife, who inform her that their children are ill and asleep upstairs, requesting she try not to wake them. Throughout the evening, Jill receives a series of disturbing phone calls from an unknown man, who at first says nothing, later asks repeatedly if she has checked the children, and finally menacingly asks why she has not checked the children. Initially dismissing the calls as a prank, Jill grows increasingly frightened and contacts the police. Authorities eventually trace the calls to another phone line inside the house and urge Jill to flee immediately. Police rush to the home and apprehend the caller, a mentally disturbed merchant seaman named Curt Duncan, who had murdered the Mandrakis children shortly after Jill arrived. Duncan is committed to a psychiatric institution, while Jill is left deeply traumatized by the ordeal.
Several years later, Duncan escapes from the institution, prompting Dr. Mandrakis to hire John Clifford, a private investigator and former police detective who originally worked the case, to track him down. Assisted by his former partner, Officer Garber, Clifford becomes obsessed with apprehending Duncan and privately vows to kill him rather than see him recommitted. Meanwhile, Duncan begins stalking a woman named Tracy Fuller after an encounter at a bar. Clifford warns Tracy about Duncan’s violent past and convinces her to help lure him out, but their plan fails. Later, Duncan attacks Tracy in her apartment, having hidden in her closet, only for Clifford to intervene and pursue him through the streets of downtown Los Angeles before losing him.
Now married with children of her own, Jill has attempted to move beyond the trauma of that night years earlier. While out to dinner with her husband Stephen, Jill receives a chilling phone call from Duncan once again asking, “Have you checked the children?” Terrified, she contacts the teenage babysitter watching her children, only to discover they are unharmed. Learning of the incident, Garber tips off Clifford. Later that night, as Jill and Stephen prepare for bed, Jill hears Duncan’s voice inside the house. Attempting to wake Stephen, she instead discovers Duncan beside her in the bed. Duncan attacks Jill before Clifford arrives and fatally shoots him. Stephen is discovered alive, bound and gagged inside their bedroom closet. As Clifford consoles Jill, Duncan’s lifeless eyes glare over the house.