The Sitter is a 1977 American short horror-thriller film directed by Fred Walton on which his 1979 feature film When a Stranger Calls is based. It is a suspenseful retelling of the classic urban legend of "The babysitter and the man upstairs" about a babysitter who is menaced by mysterious and frightening phone calls.

Plot

On the evening of March 21, 1972 in Santa Monica, California, a teenage girl named Jill Johnson is babysitting the children of Dr. Mandrakis at his house. The children have been put to bed upstairs and Jill is downstairs in the living room doing her homework. She receives a telephone call from a man who asks her if she has checked the children. Jill dismisses the call and goes back to her homework. The anonymous caller dials back several times. Eventually Jill calls the police, who inform her to keep the caller on the line long enough for them to trace the call. After the stranger calls again, the police return her call, advising Jill to leave immediately because the calls are coming from a phone inside the house. Jill runs to the door as a light comes on at the top of the staircase, and the stalker's shadow appears. The scene segues to a close-up of a detective who is investigating the matter. A policeman explains to the detective that Jill is unharmed, but the children were murdered by the killer several hours earlier.