All the Kind Strangers(1974)
OVERVIEW
An LA photographer, driving through backwoods country, spots a young boy walking on the side of the road and offers him a ride home. After reaching the isolated house, he discovers that the boy and his siblings are keeping a woman prisoner as their "mom" and now he is expected to be their "dad"...or else.
TAGLINE:
There's Nothing More Dangerous Than a Kind Face.