I've said it before and hope to again: David Cronenberg is the most provocative, original, and consistently excellent North American director of his generation. From Videodrome (1983) through A History of Violence (2005), neither Scorsese nor Spielberg, and not even David Lynch, has enjoyed a comparable run.

A rhapsodic movie directed with considerable formal intelligence and brooding power from an original screenplay by Steve Knight, Eastern Promises is very much a companion to A History of Violence. Both are crime thrillers that allow Viggo Mortensen to play a morally ambiguous and severely divided, if not schizoid, action-hero savior; both are commissioned works that permit hired-gun Cronenberg to make a genre film that is actually something else. As slick as it is, Eastern Promises could, like A History of Violence, almost pass for an exceptionally well-made B-movie.

Graphic but never gratuitous in its violence, Eastern Promises opens on a rainy December eve with a brutal gangland murder in a London barbershop and unfolds mainly in a demimonde of Russian émigré thugs and whore- masters. Anna (Naomi Watts), a midwife in a central London hospital, delivers a baby as the mother, a 14-year-old prostitute named Tatiana, dies in childbirth. Half-Russian herself, Anna filches the girl's diary, hoping to discover who she is, and asks her irascibly inebriated uncle (Polish director Jerzy Skolimowski) to translate. "Do you always rob the bodies of the dead?" he asks in a question that will hang over the rest of the movie.

A business card found in the diary brings Anna to the Trans-Siberian restaurant, administered by the grandfatherly Semyon (Armin Mueller-Stahl). That this red and gold Nutcracker wonderland turns out to be the headquarters for the London branch of the Gulag-spawned criminal fraternity vory v zakone (thieves in law) is the least of the movie's surprises. In her attempt to fathom the origins of the orphan to whom she's given the seasonal name Christina, Anna is continually bamboozled by the Trans-Siberians, a tribe whose every pleasantry carries a threat. "This isn't our world--we are ordinary people," her anxious mother (Sinead Cusack) warns her.

As usual in Cronenberg, the ordinary is severely contested terrain. (In a new scholarly treatment of the director, Mark Browning notes that nearly all of Cronenberg's post-1982 movies are designed to "problematize exactly what constitutes 'normality.' ") However naïve and depressed Anna appears, she is on a serious--and seriously deranged--quest. She's lost a baby through miscarriage and wants another one: Tatiana's. The means by which this might be achieved are at the heart of the movie, and also its strangeness.

Cronenberg's two previous works, Spider and A History of Violence, have been murderous family dramas; Eastern Promises continues this trend. Mueller-Stahl may be perfunctory in the role of the Russian paterfamilias, but Vincent Cassel literally flings himself into the role of his wastrel son Kirill, particularly in the company of the movie's most compelling presence, the crime family's chauffeur, Nikolai (Mortensen). Here is the movie's love story; in fact, the coupling of Kirill and Nikolai has the potential to fulfill Anna's dream. Hair slicked back, eyes hidden behind wraparound shades, Mortensen is even more electrifying as Nikolai than in his History of Violence roles; the actor speaks Russian as if he knows what he's saying, and his world-weary strut is at least as eloquent. Nikolai is a superbly complicated character--dark, diffident, cynical, hyper-alert, and tough enough to humorously stub out a cigarette on his tongue.

Garish yet restrained, Eastern Promises has scarcely a wasted set-up. In a close middle shot that is pure Cronenberg, Nikolai's car eases in behind Anna's parked motorcycle, a vintage Ural that belonged to her father; it's a menacing gesture that stops just short of a flirtatious caress. ("Sentimental value," Nikolai repeats when she tells him why she treasures the bike. "I've heard of that.") Nikolai is not only the family driver but their mortician: He and Kirill retrieve a dead body from the killer's freezer. Nikolai softens the corpse with an electric hair dryer. "OK, now I'm going to do his teeth and cut off his fingers," he informs his comrades. "You might want to leave room." They do, and you might wish to as well, although Cronenberg insures that we stay--at least for a few beats.

Eastern Promises is a masterful mood piece with a surplus of atmosphere. Intermittently excerpted in voice-over, Tatiana's diary is the most awkward element in Knight's otherwise impeccable screenplay--although it does introduce a current of unambiguous, otherworldly innocence in this misty, indeterminate world. Everything else is fluid. Blood flows; rain is near-constant. Corpses are tossed into the Thames, but secrets keep bobbing to the surface. Late in the movie, Eastern Promises' homoerotic subtext bursts its banks and all but floods the screen in a steamy public bathhouse with an extraordinary action sequence that must have taken a week to film.

According to the movie's characters, the world is populated by angels, devils, and human wolves. (Indeed, Eastern Promises is a Christmas story, complete with miracle.) Whenever possible, Cronenberg designs a wound that might have been inflicted by a fastidious insect from outer space, but mainly he uses a slightly wide-angle lens to keep the phantoms in sharp focus. Eastern Promises suggests a naturalized version of the recent Russian horror flick Night Watch. The vory v zakone are like a plague of vampires--governed by arcane laws and fearful superstitions. "You pronounced the name of my father," Kirill shrieks when confronted by an angry Anna. Liturgical music is heard as Nikolai kneels in his underwear, displaying his prison tattoos, for induction into the crime family. "I am already dead. I died when I was 15. Now I live in the Zone all the time," he assures his examiners.

Nikolai may be death personified but, with the possible exception of Anna's uncle, all of the Russians in Eastern Promises are walking corpses. Tatiana's diary begins by noting that the people of her village lived as though "buried in the earth." Kirill jokes that a particularly grotesque birthday celebration at the Trans-Siberia is a party for the Angel of Death. Who then will wrest the infant Christina from her clammy birthright?

Deceptively generic, Eastern Promises features Cronenberg's most unambiguous monster and straightforward narrative in years; the movie is a cosmic struggle between good and evil. But it's also an elaborate game that's played out in a fallen world filled with subterfuge and delicately limned with the pain of exile. (It hardly seems coincidental that Nikolai's last name, Luzhin, would be that of the chess-master hero of Vladimir Nabokov's The Defense.)

"I need to know who you are," Anna urgently begs this ambiguous redeemer in the movie's haunting penultimate scene. Is our Nikolai an angel, or has Anna made a deal with the devil? And suppose that amounts to the same thing? As the sardonic Nikolai might say: "What does it matter?"