Due to their possession of an ancient mystic book, four friends are attacked by a demon while on a picnic and find themselves pitched into a world of evil that overlaps their own. The film was originally made in 1967 by Dennis Muren as The Equinox: Journey into the Supernatural. Jack Woods was hired to shoot additional footage and expand on Muren's work.

Deep within the woods and canyons of California, four teenagers happen upon an ancient book containing the secrets of a strange, malevolent world that coexists with that of mankind. This film was re-editted with additional footage and released as Equinox (1970).