It begins with a departure and ends in a homecoming, but Wong Kar-Wai's Cannes Best Director winner is really a film about the dream of travel. It is too a film of travel, with the celebrated Hong Konger and his brilliant cinematographer - Australian Chris Doyle - leaving the neon-splashed hothouse of Wong's home for South America.

They, like the gay lovers of their film, fetched-up in Buenos Aires, anticipating the brochure-promised sun-dappled climes, but found instead the numb shades of an autumnal Europe. That run-down, slightly drunken atmosphere infects the film's every frame; this is a largely organic film-making technique.

The lovers - Leslie Cheung (Ho) and Tony Leung (Lai), both Asian superstars and both excellent - are sour young men looking to be "happy together". Their lives are a ritual of splits and reconciliations, unable, it seems, to resist the notion of "starting over". This Argentinean sojourn, however, leaves them penniless and finally apart for good when the flighty Ho disappears.

A strange country rather concentrates Wong's disparate storytelling, making this a far more structured, less frantic exercise than breakthrough romance Chungking Express or that hallucinatory frenzy, Fallen Angels. If anything, Happy Together resembles the more conventional As Tears Go By, albeit imagined through Doyle and Wong's rich visual vocabulary. Slo-mo, step-frames and frenetic editing echo an interior life, from initial melancholic monochromes to the saturated colours of the couple's sweaty, chaotic one-room apartment. The film dispenses with its one major sex scene at the outset, neatly side-stepping the issue later when we have been so fully visually inculcated into the boys' affair. The film, emotionally, lives inside Lai's head, particularly in the liberating visual exuberance of his eventual return home. His and our journey is at an end.

Happy Together successfully develops his palette just when Wong Kar-Wai, through no fault of his own, looked like becoming a pop-video cliché. Seldom have visual authority and emotional resonance been so in harmony. Again he proves his film-making to be a triumph of substance over style, warning us that, as his genius filters through to the Western mainstream, we should not hold him to blame for the muddleheaded copyists.