Equinox

More 70's mayhem.

Four university students go on a picnic to meet with a professor needing their help only to and encounter a creepy forest ranger and a crazy old man. The professor is a scientist who had found a mysterious book bound in human skin and when he had read/interpreted its weird symbols it released monsters from hell. The students hang on to the book, but are then chased by monsters, and the devil himself disguised as a park ranger.