Chiwetel Ejiofor doesn't need to be a movie star. The friendly 26-year old British actor has a prodigious reputation and a wealth of opportunities on the London stage. But Chewy--as he's informally known--thinks Hollywood might be an interesting destination. His breakthrough performance in Stephen Frears' brilliant Dirty Pretty Things, a thriller set amid the British capital's illegal-immigrant community, could well be his passport.

The outstanding Ejiofor plays Okwe, a refugee from a tragic past in his native Nigeria, living under the radar in London. "He's absolutely trying to be as invisible as possible," said Ejiofor during a phone interview. "That's a choice he's made--to have no connection with anybody--because it's a reminder of what he's lost."

Formerly a respected pathologist in Africa, Okwe survives by working days as a minicab driver and nights as a hotel porter, hardly sleeping in between--a member of an unacknowledged fringe, taking on the drudgery of an oblivious metropolis. Okwe is a composite of cinematic heroes, a slave and a fugitive who overcomes tyranny and strikes a blow for the underdog, but also a principled everyman thrown into a dangerous, immoral realm and challenged to escape. Cinemagoers in America--a country standing on the shoulders of its immigrant workers--should embrace such a hero.

Ejiofor, born and raised in London to Nigerian parents, delivers a moving performance of pregnant restraint and integrity, communicating through anguished eyes the hopelessness of a man adrift, whose only objective is to handle each unpleasant day in this grimy ghost world without leaving a fingerprint. But this Teflon life becomes unsustainable as Steve Knight's clever script draws Okwe into irresistible human relationships and a grisly intrigue, beginning with a macabre discovery: a human heart in a hotel toilet bowl.

In the hands of Frears (The Grifters, High Fidelity), a director who relishes telling outsiders' stories in exciting ways, Dirty Pretty Things becomes an amalgam of provocative social drama and heart-stopping crime thriller. The film "does create a whole new format, a symbiosis of things that immediately seem like they don't belong on the same film, but actually can do to a great effect," says Ejiofor. "[Frears] says he 'put the car chases in,' and I know what he means."

While Frears steers clear of actual car chases, Dirty Pretty Things maintains a fast-paced tension as Okwe and his roommate, Senay (Audrey Tautou), are forced to evade immigration officials and outsmart despicable hotelier Juan (Sergi López), who manipulates both with the promise of forged passports. Central to the film is Okwe's friendship with mortuary attendant Guo Yi (Benedict Wong). Guo Yi is a conduit to Okwe's past life and his only remaining vestige of

normal social interaction. The friends share jokes and play chess, and it's Guo Yi to whom Okwe turns for help and advice. "It's a vital relationship in the film, because I think without that, the character gets a bit bleak," explains Ejiofor.

The often-jovial relationship makes Okwe one of us but also captures the way human nature invariably overcomes the most terrible circumstance. In Ejiofor's words, "It's the kids playing on the rubble."

In her first English-speaking performance, Tautou (Amélie) co-stars as Turkish asylum seeker Senay, another forgotten soul toiling in the abyss of the aptly named Baltic Hotel. The performance is beautifully understated, her imploring cocoa eyes capturing the vulnerability of a naive girl mired in a corrupt environment.

Dirty Pretty Things' theme is of a world that corrupts, a purgatory that debases lost souls, even the good at heart. There are frequent visual references to infection and cleanliness, like Okwe's fastidious attempts to remain unsullied, from washing glasses to sterilizing surgical instruments. "There's this real emphasis on sterility in the film," says the actor. "I think it's a representation of a world that you can get your hands dirty in, and these people are desperate to rid themselves of that."

The film has been a critical success in Britain. Its social realism addresses the issue of immigration, so often sensationalized by the national press, and treats it with compassion. Apart from Pawel Pawlikowski's Last Resort, U.K. cinema has mostly ignored the plight of immigrants and asylum seekers. U.S. cinema has been similarly neglectful. A shame, says Ejiofor, but something unsurprising in context. Summarizing Dirty Pretty Things, he says, "It's about people who aren't dealt with in mainstream society, which would include films."

Dirty Pretty Things

Rated R

Opens Friday, Aug. 15.

Fox Tower.

Steve Knight, who wrote the screenplay for Dirty Pretty Things, has a knack for suspenseful entertainment: He was one of the creators of the gameshow Who Wants to Be a Millionaire?.