In 1691 Boston, the witch-hunter Giles Redferne, portrayed by Richard E. Grant, sentences a dangerous Warlock to death for his dark activities, including the fatal injury to Redferne’s wife. But a sinister force—Satan—snatches the Warlock and thrusts him through a portal into the late 20th century, landing him in Los Angeles, where Redferne himself chases through time with a relentless sense of duty.
The Warlock crash-lands at the doorstep of a waitress named Kassandra, brought to life by Lori Singer, and her roommate Chas, who is played by Kevin O'Brien. Before they can fully understand what’s happened, the Warlock murders Chas, and a perilous quest begins: reassemble the Grand Grimoire, a three-part grimoire that has the power to unmake Creation itself. In the aftermath, the Warlock wields the first piece like a cruel prize, using the severed eyes of a psychic as a crude compass to locate the hidden segment inside an old antique table at Kassandra’s home. The Warlock’s thirst for renewed youth pushes him to seize power, including an aging curse placed upon Kassandra and the theft of her bracelet, which would have granted her youth if not interrupted.
Redferne arrives with a witch compass to track the Warlock and explains some basic rules about witches and warlocks—weaknesses such as purified salt and other ancient protections. To help in the chase, Kassandra follows him, intent on reclaiming her bracelet and understanding the looming threat. Meanwhile, the Warlock’s hunger for power grows as he gains the ability to fly after murdering an unbaptised boy, a grim testament to the prices paid to advance his plans.
The pursuit drives them to the rural home of a Mennonite family, where Redferne, Kassandra, and the Warlock collide in a fierce struggle that centers on the second piece of the Grimoire. The Warlock’s flying attempt is thwarted by a weathervane made of cold iron, and a subsequent attempt to bind him with manacles fails as he hexes the Mennonite farmer with the Evil Eye and escapes on foot. The trio—Redferne, Kassandra, and the Mennonite couple—work to subdue the Warlock, with Redferne delivering a crucible of protection while the farmer’s wife tends to the injuries.
A brutal turn follows as the Warlock sheds his shackles and escapes by train, yet Kassandra manages to recover her bracelet, restoring her youth in the process. The farmer is grievously injured, but Redferne leaves him a form of aid in the shape of bronze keys. With a grim warning that the Warlock intends to destroy the universe, Kassandra is urged to press on and not give up, driven by the belief that their foe will not relent.
The chase carries them to Boston, where the final piece of the Grimoire is said to be buried on sacred ground. They warn the Church and its pastor of the impending threat, and a plan unfolds: the Grimoire is buried in sacred earth, but a graveyard shift reveals that several coffins have been moved away from consecrated ground. They discover Redferne’s own coffin and break it open to retrieve the Grimoire, only to have the Warlock force the pastor to reveal its final resting place by threatening to cause his wife’s miscarriage.
With the Grimoire in hand, Redferne carries it onto hallowed ground, and the Warlock demands the book. A fair fight is proposed—no weapons, no magic—but the terms quickly blur as Kassandra is flung into a lake and the Warlock takes the upper hand. Redferne cheats by throwing soil from sacred ground into the Warlock’s face, tipping the balance in a deadly contest that ends when the Warlock, empowered by magic, seizes the final third of the Grimoire and reveals the name of God written on the book.
In a final, desperate move, Kassandra drives a syringe packed with salt water into the Warlock’s neck, stalling his power as his throat seals shut and he erupts into flames. The two heroes bid each other farewell as Redferne returns to his own era, and Kassandra buries the Grimoire in the middle of the Bonneville Salt Flats, sealing its fate once again and closing the door on a perilous journey through time.
