Glen and his friend, Terry, discover that the hole in the yard is actually a gateway to the domain of demonic "Old Gods" who once ruled the universe (they make this discovery after listening to a heavy metal album). The album is actually a Satanic Bible called "The Dark Book". They realize that the demons are going to set up their hell on earth and take back what is theirs, in order to rule the universe once again. Creatures climb out of the gate to capture two of the kids in order to sacrifice them. Glen and Terry attempt to stop the creatures by reading Bible passages and reciting heavy metal lyrics backwards, but are only able to briefly slow the creatures down. Soon Terry and Al are captured by the Workman, a zombie-like demonic henchman. They are then led down the hole, and sacrificed. Evil floods out of the hole and a giant, multi-limbed, serpent-like Demon Lord causes an eye to grow in the palm of Glen's hand. Glen stabs the eye and fires a rocket that Al intended to give him for his birthday, a form of light and love, at the Demon, destroying him and stopping the invasion. Terry and Al return, restored and unharmed. There is a sequel called The Gate 2
This movie is rated PG-13, containing colorful language, violence, intense images, and disturbing situations.
The movie utilizes stop motion, Harryhausen-esque creatures that torment the characters throughout the film.