Richard Crouse

The release of “The Omen” in 1976, made the name Damien synonymous with darkness and evil. Unbeknownst to wealthy U.S. diplomat Robert Thorp (Gregory Peck) and wife Katherine (Lee Remick), their adopted son, five-year-old Damien (Harvey Stephens), is the Antichrist, the ultimate agent of anarchy.

That movie was a controversial sensation, and before you could chant, “Sanguis Bibimus,” it spawned big box office, a few sequels, a remake, a television show and a series of books.

A new prequel to the original film, “The First Omen,” now playing in theatres, aims to respond to a question left unanswered by all that came before it: How and why did Damien come into existence?

Set in 1971, the new movie stars Nell Tiger Free as American novitiate nun Margaret Daino, a young woman with a troubled past that includes hallucinations that she sometimes thinks are real.

Sent to work in an orphanage in Rome, she arrives as a general strike has brought the city to a standstill. Workers want more money, while students are protesting, rejecting authority and, more troubling to Cardinal Lawrence (Bill Nighy), the church. “The world is changing fast,” he says. “The young are no longer turning to us.”

Her faith is rocked when she uncovers a conspiracy to conjure up an antichrist to sow the seeds of chaos, and drive people back to the church.

“How do you control people who no longer believe?” asks Father Brennan (Ralph Ineson). “You create something to fear.”

“The First Omen” is an origin story that casts a wide net as it explores themes of both religious and body horror and a detective story of a sort. Director Arkasha Stevenson’s movie dovetails nicely into the original, using some of the same characters and new twists on some of the most memorable scenes from the 1976 film. But it also takes a helluva lot of time getting where it is going.

Like the recent, and similarly themed “Immaculate,” the juicy stuff is saved for the third act. Until then, it more or less marinates in the idea of evil, throwing a clue here, a bit of gore there. It’s uneven, but sets the scene, provides a scare or two and proves Free is capable of carrying the mystery at the centre of the story, even if it goes on a bit too long.

But it is in its exploration of body horror and the anguish of abuse that “The First Omen” finds its feet. For a time anyway. The climatic sequence is shocking, with disturbing images that provide a horrific payoff. If it ended there, “The First Omen” would go out with a visceral and thematic bang.

But the devil is in the details, and there are a few too many details and false endings before the end credits roll, blunting the primeval effectiveness of the climax.

You do not have to have seen “The Omen” to understand “The First Omen.” The new film has enough disturbing ideas to stand on its own, but feels protracted and lacks the gothic elegance of the original.