One evening the Collins find their maid Mrs. Murdock at the end of their steps: dead, neck broken. Obviously she had an accident. Consequently they need a new babysitter for an upcoming big party. The sensible Helen meets little Susan Collins at the discount market and likes her, so she offers to do the job. She doesn't know Susan's teenage brother Mark - technically skilled and good in school, but restive and cunning. As soon as the parents have left, he starts psychologically terrorizing Helen and his sister with electronic tricks.
as Helen Giles
as Mark Collins
as Nell Kempler
as Evelyn Collins
as Phillip Collins
as Susan Collins
as Jim Kempler
as Karl Yaeger
as Peg Yaeger
as Sheriff
as Deputy
as Williams
as Jeanette
as Metz
as Chemistry Teacher
as Sam, the Grocer
as Pharmacist
as Elsworth Peale
as Mrs. Peale
as Mrs. Murtagh
as Cybelle
as Orator
as Paramedic
as Kaye
