A dark mystery leads a London woman into the dangerous underworld of Russian mobsters in a tense new thriller from director David Cronenberg, co-starring Viggo Mortensen and Naomi Watts. Alan Silverman has a look at Eastern Promises.

Midwife Anna Khitrova is working her shift at a London hospital when the pregnant teenager dies while giving birth. Along with the newborn, the girl leaves behind a diary written in Russian. Her search for the baby's family leads Anna, who herself is of Russian heritage, into an underground society filled with danger:

Naomi Watts plays Anna and says the character knows there is risk, but she is determined to learn the truth about the baby and its unfortunate mother.

"I loved that she was intrigued and it awakened her," says Watts. "She was sort of living in a depressed state and not really connecting with anything and hiding behind her work. This awakened her spirit and taught her more about herself and her identity - the whole Russian side of herself that she, perhaps, denied being a first generation (child of immigrants). It gave her meaning in her life."

Among the people she meets is the taciturn and mysterious Nikolai who is the driver for a ruthless crime boss; but, as Anna learns, in this underground society everyone has secrets and may not be who they appear to be.

"As much as it is about brutality and cultural misunderstandings and intolerance and lying, deceit and savagery, it is also a movie about kindness and compassion ...surprisingly so, I think," says Viggo Mortensen, who co-stars as Nikolai.

"It was important to get the language right to sound Russian and (use) the inflections when not speaking Russian, the grammar and particular slang and syntax of a person from his walk of life ...that helped me a lot," he says. "I did meet a few people that were, more or less, from Nikolai's walk of life that I normally would not meet - and why would I want to? - but in this case they were very helpful," Mortensen explains. "It wasn't so much the information as the way they would explain it: how they would look at me and be aware of their environment as they were doing so. All those things were interesting to me as an actor trying to soak up as much as I could."

Mortensen, famous for his Lord of the Rings role, delved into a dark, criminal world once before with director David Cronenberg in 2005's A History of Violence. The filmmaker says their collaboration on Eastern Promises aimed at a realistic and accurate portrayal, down to the elaborate and meaningful tattoos on the bodies of the gangsters.

"The tattoos are your passport in a prison. The whole story of your life is tattooed onto your body so that people can see who you are. You can't hide who you are: what crimes you've committed, what your sexual orientation is, where you've done time in prison and for how long. All of these things. It is your identity, really, tied up with the tattoos," he explains.

In one breathtaking fight scene, the audience gets to see all of the 40-odd tattoos on the body of Nikolai who is in a steam bath when he is surprised by knife-wielding assassins.

"It is about betrayal because he is brought there by a man he trusts and then is betrayed; and it is about vulnerability," explains Cronenberg. "Anybody can relate to that. In a way, weirdly enough, it is almost like the shower scene in Psycho: a woman attacked by a man with a knife while she is taking a shower. That sense of vulnerability is really why the scene is placed there. So it is a fight scene that has our hero being as vulnerable as you could ever possibly be. That is really what it is about."

Mortensen, in his matter-of-fact way, says he realized when they were rehearsing the scene that he would have to do the fight naked in order for it to be believable.

"To me if you do something right you do it realistically (and) there is a satisfaction in doing that. It is not a gratuitous scene," he explains. "People remark on it and I understand why; but why have one scene that stands out for being unrealistic in a movie that is so grounded in reality?"

One of the tattoos in Cyrillic letters on Nikolai's back reads 'the important thing is to remain human' and Mortensen believes that is at the heart of the story.

"I do think that as brutal and hard and cold as some of the people in this story are and the story itself seems to be, in the end," Mortensen says, "for me, it is about kindness and compassion in spite of big obstacles to behaving that way ...to showing any kindness. To some degree it is about what a character will do in a complicated world to help someone who can't help themselves."

Eastern Promises also features German screen veteran Armin Mueller-Stahl as the seductive crime boss Semyon; French actor Vincent Cassel plays his bad-boy son Kirill. The screenplay is by Stephen Knight and much of the film was shot on location in the Russian émigré neighborhoods of London.