Warlock is a 1989 American supernatural horror film directed by Steve Miner and written by David Twohy. Julian Sands stars as the title character, a son of Satan who travels from the late 1600s to modern times with the mission of destroying the world. Lori Singer and Richard E. Grant co-star as a 20th century woman and a 17th century witch-hunter attempting to stop him.
The film was shown internationally in 1989, but did not receive an American release until January 11, 1991. It received mixed reviews and grossed $9 million on a $15 million budget. Two sequels would follow, Warlock: The Armageddon in 1993 with Julian Sands reprising his role, and a straight-to-video release titled Warlock III: The End of Innocence starring Bruce Payne in the role.
The Warlock is taken captive in Boston, Massachusetts in 1691 by the witch-hunter Giles Redferne. The Warlock is sentenced to death for his activities, including the death of Redferne's wife, but Satan propels the Warlock forward in time to late 20th century Los Angeles, California. Redferne follows through the portal.
When the Warlock crash lands in the flat of a waitress named Kassandra and her roommate, Chas, he is taken in by them. While Kassandra is out, the Warlock murders Chas. The Warlock confronts a fake psychic, tricking her into allowing her to be possessed by Satan who tells him to reassemble The Grand Grimoire, a book separated into three pieces which can unmake Creation. Ripping out the psychic's eyes and using them as a compass, the Warlock finds the first piece of the Grand Grimoire hidden inside an antique table at Kassandra's flat. While there, he places an ageing curse upon her and takes her bracelet. Redferne arrives with a "witch compass" to track the Warlock. After Redferne explains some basic rules of Witches and Warlocks, such as their weakness to purified salt, Kassandra follows him in order to regain her bracelet, which will allow her to become young again. The Warlock acquires the power of flight by murdering an unbaptised child.
Redferne and Kassandra pursue the Warlock to the rural home of a Mennonite family where the Warlock has located the second piece of the Grimoire. After a battle with Redferne, the Warlock attempts to fly away but is struck down by a weathervane made of cold iron. Redferne, Kassandra and the Mennonite couple attempt to bind him with a pair of manacles that will stop him from using his power, but the Warlock hexes the Mennonite farmer with the Evil Eye before escaping on foot. Redferne gives Kassandra a blessed hammer with which to hammer nails into the Warlock's footprints while he and the farmer's wife carry the ailing farmer back to the house. While the Warlock sheds his shackles, Kassandra hammers nails into his footprints, causing the Warlock agony. He escapes via a train but Kassandra recovers her bracelet, restoring her youth. The farmer is terribly injured, but Redferne leaves him a cure in the form of bronze keys. Kassandra is persuaded to continue on when Redferne tells her that the Warlock intends to destroy the universe.
They follow the Warlock to Boston, where the final piece of the Grimoire is supposed to be buried on sacred earth. They arrive at the Church where the Grimoire is held and warn the priest that the Warlock is coming for it. The priest reassures Redferne and Kassandra that the book is buried in sacred earth, directing them to a graveyard. Kassandra realises that due to construction, many coffins have been moved to a part of the graveyard that is not consecrated ground. They find Redferne's coffin and break it open to get the Grimoire when the Warlock arrives, having forced the priest to reveal the location of the book by threatening to give his wife a miscarriage. Redferne carries the book onto hallowed ground but the Warlock threatens to kill Kassandra if Redferne does not bring him the book. Redferne challenges the Warlock to a fair fight without weapons or magic and the Warlock agrees. He flings Kassandra into a lake and he and Redferne fight. The Warlock gains the advantage and Redferne cheats by throwing soil from the sacred ground in the Warlock's face. With the rules broken, the Warlock uses his magical abilities to subdue Redferne and claim possession of the final third of the Grimore.
Before the Warlock can use the Grimoire, Kassandra stabs him in the neck with the syringe she uses to inject insulin, which she filled with salt water from the lake. The Warlock's throat seals shut and he bursts into flames. Redferne and Kassandra bid one another farewell before Redferne returns to his own time. Kassandra buries the Grimoire in the middle of the Bonneville Salt Flats.