"I am driver," explains Viggo Mortensen early in David Cronenberg's Eastern Promises. "I go left. I go right. I go straight ahead. That's it." In fact, moviegoers should be pleased to know that the moral maneuvers undertaken by Mortensen's character, a low-level hood in London's Russian underworld, are considerably more interesting than advertised: swerves, veers, dips, even a u-turn or two. In structural terms, the protagonist of the film is a midwife played by Naomi Watts.