Michael Winterbottom is such a consistently interesting filmmaker, it's easy to forgive the cold, clinical eye he focuses on his subjects and the subdued, emotionally distant deportment of his players.

With the futuristic tale "Code 46," that laboratory detachment actually underscores Winterbottom's themes of a dehumanized society divided among the privileged few and the miserable masses stuck in underdeveloped wastelands.

For his first film since winning the supporting-actor Academy Award for "Mystic River," Tim Robbins takes a very different turn from that showy role, demonstrating impressive subtlety as a man who risks his cozy life in a fling with a forger.

With her every expression a cipher, Samantha Morton, an Oscar nominee for last year's "In America," is ideally suited for the Winterbottom school of poker-faced passion.

Building on the dispassionate chemistry of his two leads, Winterbottom crafts a fresh, brainy sci-fi tale with a great deal to ponder about the potential extremes of our have and have-not society and the directions border paranoia and genetic tinkering might lead.

Written by Frank Cottrell Boyce and produced by Andrew Eaton, Winterbottom's collaborators on such films as "24 Hour Party People" and "The Claim," "Code 46" is set in a near future when travel is severely restricted.

The prosperous live in cities with nearly impenetrable security checkpoints, and only those possessing "papelles" — all-in-one insurance coverage, passport and visa documents — are free to gain entry. Hordes of others live in desert shantytowns, with no hope for a better life.

Robbins plays William, an insurance investigator from Seattle sent to Shanghai to look into a case of faked papelles. William quickly identifies the forger as Maria (Morton), an employee for an insurance conglomerate.

Smitten with Maria, William fingers another co-worker. He and Maria engage in an affair with a time limit — William's papelle requires him to return home the next day.

Yet William cannot shake his obsession, Maria representing a depth of passion he cannot find in his numbly pleasant life with his wife and young son. William returns to Shanghai to resume the affair, eventually relying on a forged papelle himself as he and Maria try to find safe haven.

In the vein of other romances doomed by totalitarian states, such as George Orwell's "1984," George Lucas' "THX 1138" and Terry Gilliam's "Brazil," William and Maria run afoul of "Code 46," a law strictly regimenting breeding in a world where cloning presents dangers of undesirable genetic consequences.

The lack of high-tech gadgetry and visual effects is an advantage for "Code 46," keeping the focus firmly on the characters and their pitiable stab at love.

Though far less harsh than "1984," "THX 1138" or "Brazil," the outcome of William and Maria's romance is profoundly tragic, and the Sphinx-like Morton provides a heartbreaking final image to the film.

"Code 46" is rated R for a scene of sexuality, including brief graphic nudity. Running time: 93 minutes.