Dir: Alejandro Gonzalez Inarritu. USA. 2003. 124 mins.

Emotionally draining but formally brilliant, the long-awaited second feature by Mexican director Alejandro Gonzalez Inarritu is for those of us who are passionate about cinema, and who don't mind taking a few body blows in a dark room in the process. The high profile of the film's three leads - Sean Penn, Naomi Watts and Benicio del Toro - will help it reach a wide audience sooner than Amores Perros, which was a real word-of-mouth sleeper hit. But if the intertwined stories of love and death in 21 Grams build slowly into a complex whole with real moral depth, they do so at the expense of the in-your-face animal energy of Gonzalez Inarritu's debut. Focus Features, which edged out Miramax in the bid to produce and distribute, will need to target this dark and edgy work carefully, and rely heavily on critical plaudits and on an Oscar campaign which took its first tentative steps at the Venice Film Festival, where this competition film earned Penn the best actor award and Del Toro and Watts audience plaudits.

21 grams is the amount of weight a human body loses in the few seconds after death: the weight of the soul, some would claim. It's a clever title - one that generates a word-of-mouth buzz independently from the film itself. But its relevance to the storyline is as opaque as the storyline itself, at least in the first 40 minutes.

We identify the three main characters soon enough: Paul (Sean Penn), a university professor of mathematics who is waiting for a heart transplant; Cristina (Naomi Watts), a former party girl who has settled down to a life of domestic contentment with her architect husband and two daughters; and Jack (Del Toro), a violent ex-con who has become a passionate, but screwed-up, Jesus freak. But it's less easy to work out how they're connected. The narrative switches back and forth between their lives; but it also jumps back and forth in time, showing scenes which we gradually realise come from later in the film - first of Paul and Cristina together, then, in a burnt-out motel on the edge of a no-hope town, a violent scene featuring all three, which finally yields its secret right at the end. It's only around forty minutes in that the most sluggish of the film's three (or is it more') timeframes makes it to the car crash which - as in Amores Perros - welds the apparently unrelated stories together in a tight mesh of fate.

As a formal exercise, it's stunning. There's a scene near the beginning where Benicio del Toro is playing Jenga with a streetkid in the evangelical mission he hangs out in: and the wooden tower which will collapse if we take out the wrong piece can be read as a metaphor not only for the fragility of human life, but for the delicate balancing act of the film's structure.

Rodrigo Prieto's textured camerawork adds its 21 grams to the movie's ravishing aesthetic, using grainy stock and the bleach-bypass process already exploited in Amores Perros to tweak the look of this drifting, centreless America town (actually Memphis, Tennessee) away from the everyday. But there are moments when this elegance of form compromises our emotional commitment to the characters and masks certain weaknesses in their motivation: as, for example, when Cristina turns murderous. Penn is good as ever, Watts better than ever before; but the real standout performance comes from Benicio Del Toro as a kind of latter-day Job, without the patience. If you like hard work, you'll love this film; but try not to see it after a hard day's work.

Prod co: Focus Features, This is That/Y Prods
Int'l sales:
Focus Features
Exec prod:
Ted Hope
Alejandro Gonzalez Inarritu, Robert Salerno
Guillermo Arriaga
Rodrigo Prieto
Prod des:
Brigitte Broch
Stephen Mirrione
Gustavo Santaolalla
Main cast:
Sean Penn, Benicio del Toro, Naomi Watts, Charlotte Gainsbourg, Melissa Leo