I saw a very good film on Saturday — "Eastern Promises," starring Viggo Mortensen and Naomi Watts. It’s ostensibly a thriller about the Russian mob operating in London; it’s also one of the most violent films I’ve ever seen. There’s a naked knife fight in a Turkish bath I missed most of because I just had to turn my face away from the screen. But the real reason to see the movie is the light it shines on the trafficking of girls and women and the prevalence of sexual slavery right beneath the surface of Western cities. That plot is the most interesting in the movie, and it’s unforgettably disturbing.