Every body has a story to tell, especially in a David Cronenberg film. In “Eastern Promises,” that story is written large across the body of Nikolai (Viggo Mortensen), whose extensive tattoos record his criminal history and life story. It’s not a pretty tale, and “Eastern Promises” is not a pretty film, at least in terms of subject matter. It is beautiful in its ugliness, though—a sparse, even lyrical meditation on how careless acts of cruelty and violence can have far-reaching consequences. It’s a theme Cronenberg previously explored in “A History of Violence,” which also starred Mortensen. But, while “History” followed the impact of violence on one man, “Eastern Promises” is all about how those ripples can extend throughout a family and, sometimes, into another.

Cronenberg starts the film with the graphic assassination of a captain in the Russian mob and, from the beginning, makes it clear that the London depicted in the film is not the same London where you visit Big Ben and get your picture taken with palace guards in big furry hats. Cronenberg’s London is perpetually wet and gray and populated by two classes: the predators—characterized here by the vory v zakone (the Russian Mafia)—and the prey—everyone else. Anna (Naomi Watts), a midwife at Trafalgar Hospital, finds herself in the latter category when she comes into possession of the diary of a young Ukrainian girl named Tatiana, who died during childbirth. Anna, whose father was Russian, brings news of the diary to Semyon (Armin Mueller-Stahl), a Russian restaurant owner whose business card Anna finds in the diary. Ostensibly a kindly old restaurateur, Semyon is actually head of the vory v zakone. Getting back the diary and taking possession of Tatiana’s baby girl become Semyon’s primary focus, as both implicate him in some particularly nasty dealings.

Anna’s quest for information also brings her into contact with Nikolai, a gang member who is partnered with Semyon’s son, Kirill (Vincent Cassel). As Anna navigates through London’s underworld, a move that endangers her mother and Russian uncle, Nikolai finds himself caught in an ongoing battle between the hot-tempered, brutish Kirill and the methodically vicious Semyon.

“Eastern Promises” may be one of Cronenberg’s most accessible, audience-friendly films. That is to say, there are at least a couple of uplifting moments and no one is disfigured too horribly or turned into a freakish mutant by a botched science experiment. But “Promises” is still a Cronenberg film. The camera lingers for uncomfortably long periods over awkward moments and scenes of extreme violence. In an early scene, Nikolai is tasked with preparing a dead body for disposal. With an almost clinical precision, he sets about his work, and as he prepares to snip off the dead man’s fingers with a pair of shears, the viewer waits for the camera to cut away. But it doesn’t, and you’re forced to watch as one finger, then another, is hacked off. Cronenberg isn’t just establishing Nikolai’s fearsome reputation here—he’s bringing audience members deeper into Nikolai’s world, while reminding them that Nikolai’s world isn’t that far removed from their own.

As much as “Promises” is a true Cronenberg film, it also belongs almost wholly to Mortensen. With a slicked-back pompadour and a soft smile that’s at once paternal and predatory, Mortensen is in total control of the movie. As Nikolai, he exudes a menace that bolsters the film’s already overwhelming sense of dread. Oddly enough, the audience doesn’t get a full display of the violence of which Nikolai is capable until a fight scene in a bathhouse near the end of the film. Already somewhat legendary because of Mortensen’s full-on nude performance, the bathhouse brawl is an astonishingly brutal piece of filmmaking that will probably be the standard by which all other fight scenes are judged for the next few years. It’s not so much a revelation as a confirmation of Mortensen’s character, and the consequences of the fight abruptly change the film’s rules.

The rest of the cast is just as brilliant as Mortensen, especially Armin Mueller-Stahl. With only a few disapproving glances and low growls, Mueller-Stahl makes Semyon into a villain who is absolutely terrifying, even though his capacity for inhumanity is never explicitly shown. Naomi Watts turns in a fine performance as well, but in the presence of circling sharks like Semyon and Nikolai, there’s little her character can do to stand out.

During a string of scenes that culminate with the bathhouse fight, Nikolai’s tattooed body is on fully display, an ornate crucifix on his chest and a stylish rendition of the Cathedral of the Resurrection in St. Petersburg on his back, among others. By the time “Eastern Promises” ends and Nikolai, Anna and the rest are left to ponder their separate fates, it’s easy to wonder how the events of the film will be tattooed on Nikolai’s body. Whatever the illustration, it would probably be a lot like the film itself—simple, subtly vicious and impossible to turn away from.