This science fiction film tells the story of Melodye Amerson (Kim Darby), a young teacher who goes to a remote area to work with a group of individuals who have isolated themselves from civilization and maintained an independent community, vaguely similar to the Amish or a religious commune. Melodye is unnerved by the secretive behavior of her students, and the fact that all fun, games and activities she proposes are forbidden to them. Valancy (Diane Varsi), an elder in the community, advises Melodye to stay, because she senses that things are about to change in the valley, and Melodye herself is a part of that change.
Melodye soon discovers that the secluded and "backwards" residents are actually aliens with mild paranormal powers. A natural disaster destroyed their planet, and they are hoping to establish a life on Earth. Landing in the late 1800s, initially they shared their secret with local residents, but found themselves condemned as witches. Many were killed, and the survivors forbade their children ever to use their abilities, even with extreme discretion. Young adults like Valancy (and even some of the older people) have been pushing for an end to these restrictions.