The Guardian is a 1990 American supernatural horror film co-written and directed by William Friedkin, and starring 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 discover the nanny to be a hamadryad, whose previous clients' children went missing under her care. The film is based on the novel The Nanny, by Dan Greenburg.

Plot

Molly and Allan Sheridan leave their two children in the care of a new nanny, Diana Julian. Diana, who is in fact an ancient Hamadryad, kidnaps their infant daughter, taking her to a forest where she approaches a giant, gnarled tree, serving the child as a human sacrifice to sustain the tree's life. As she stares into a pool of water, Diana's reflection transforms to that of a growling wolf.