Phil (Dwier Brown) and Kate (Carey Lowell) have a baby boy named Jake. They hire a baby-sitter, Camilla, to look after Jake and she becomes part of the family. The Sterling's friend and neighbor, Ned (Brad Hall), takes a liking to Camilla (Jenny Seagrove) and asks her out. She refuses, but Ned follows her and discovers that she is not quite human. Camilla discovers that she has been followed and Ned is pursued. He leaves a desperate message for Phil and Kate which reveals that Camilla has special plans for baby Jake.
The Guardian is a 1990 American horror film co-written and directed by William Friedkin (The Exorcist [1973]), and stars Jenny Seagrove as a mysterious nanny who is hired by new parents, played by Dwier Brown and Carey Lowell, to care for their infant son; the couple soon discovers the nanny to be a Hamadryad whose previous clients' children went missing under her care. It is based upon the novel The Nanny by American novelist Dan Greenburg.