In London, Okwe, an illegal Nigerian immigrant (Chiwetel Ejiofor) works two jobs: days he is an unlicensed cab driver, nights he is the desk clerk at the upscale Baltic Hotel. He rents couch space in the apartment of a maid from the hotel, Senay (Audrey Tautou), also an illegal immigrant, from Turkey. And he subsists without sleep on coca leaves he buys from a friendly store owner. But Okwe is in fact a physician, on the run from a brutal Nigerian regime, and in danger of his life if he should return home; and Senay is trying to live her fantasy of somehow reaching New York.

Director Stephen Frears, whom Americans first met with his "My Beautiful Laundrette," also about immigrants in London, has since solidified his reputation, working on both sides of the Atlantic, with "Dangerous Liaisons," "The Grifters" and most recently "High Fidelity." Here he gives us the unending tension of lives spent in the shadow of blackmail, exposure and deportation.

One night a hooker, Juliette (Sophie Okonedo), tells Okwe, manning the hotel front desk, that there's an overflowing toilet in Room 510. When he investigates he finds that the blockage is a human heart. Juan, his boss (Sergi Lopez), known as Sneaky, tells him not to worry; but Okwe is drawn in to a bloody racket that uses the hotel rooms for its work - a work I will not reveal here. And Senay, hit on once too often by Sneaky, leaves to do factory work, but finds herself a victim there also. In a sense Sneaky is the glue that holds the plot together, as it is he who provides Okwe and Senay with both a kind of imprisonment and the opportunity to escape

But "Dirty Pretty Things" is not a thriller, nor a horror film, though there is both thrill and horror in it. Frears is much too thoughtful a filmmaker to settle for anything less than a study of two fascinating people who are both compelling on screen. Ejiofor, a London stage actor, gives a beautifully understated performance as Okwe, who whether frightened by his varied nemeses or in actual danger somehow retains his dignity and articulate intelligence. Tautou, with that little-girl overbite and a shaky Turkish accent that keeps threatening to devolve back into French, nevertheless is also a believable figure here. Lopez, witty, smart, calm always, is a wonderful villain who may not actually be as evil as he seems.

The film was shot by Chris Menges, one of the supreme cinematographers of our era, with "The Killing Fields," "The Mission," and "The Pledge" to his credit. His framing and his interior lighting are worth studying by anyone interested in film as an art form. Oddly, the script is by Steve Knight, whose claim to fame is that he created "Who Wants to Be a Millionaire." This film should help restore his reputation for serious work.