Well worth suffering for

The Greek tragedians resolved any difficulties in their plots by the use of a device called deus ex machina. Sometimes this was literally a god (or at any rate a thespian playing one), lowered on to the stage in a golden chariot. In Alejandro Gonz·lez Iñ·rritu's directorial debut, Amores Perros (2000), the deus ex machina, in the form of a thugdriven pick-up truck, created terrible difficulties for the characters; and in his new film, 21 Grams, once again a fateful truck accident is the engine for the whole plot.

This time it's driven - suitably enough - by a born-again ex-con, Jack Jordan, played by Benicio Del Toro. The collision between Jordan's careering vehicle and Cristina Peck's (Naomi Watts) husband and young daughters, is the very nub of fate.

Iñ·rritu and his screenwriter Guillermo Arriaga, have said that the way the narrative of 21 Grams is built up out of a complex pattern of flashbacks and flash-forwards is intended to make the viewer feel a greater emotional complicity in the destinies of the characters.

Further, as with the first film they collaborated on (together with cinematographer Rodrigo Prieto), the exclusive use of hand-held camera makes a participant of the cinemagoer, condemned as he is to witness events from point-blank range, zeroing in on faces distorted by pain and loss.

I beg to differ. While in no way denying that both script, direction and photography deliver a hefty blow to the psychic solar plexus, as the film progresses it is the pain of knowing that the inevitable cannot be avoided which hurts us mortals most. Just as Oedipus is condemned to murder his own father, despite not knowing who he is, so Jordan, Peck and the tortured mathematician Paul Rivers (Sean Penn), while complete strangers to each other, are nonetheless driven into an intimate and fatal triangulation by the elegantly pitiless geometry of Iñ·rritu's vision.

Thus God - for the purposes of 21 Grams - is a Mexican (and presumably Catholic-influenced) film director, who believes that redemption can only be achieved through suffering.

Suffering is what 21 Grams is all about. The suffering of Paul Rivers, a fortysomething philanderer whose heart is packing up and whose estranged wife, Mary (Charlotte Gainsbourg), wants to wring a terminal sperm donation out of him so she can bear his posthumous child. The suffering of Jordan, a multi-loser, whose frenzied church-going and Biblebeating cannot save him from accidental manslaughter. The suffering of Peck, a former cocaine addict, whose put-together, middle-class life ( architect husband, blonde children) is as easily deconstructed as a substandard flat pack.

It pains me, as a modernist, to say this, but whereas Amores Perros, for all its brio and attack, ultimately collapsed into artifice and sentimentality, 21 Grams soars into the chilly empyrean of first-class film-making by virtue of the most traditional of values: sympathetic characters and clever plotting.

We care about Rivers, who, as played by Penn, has a haunted, wistful dignity about him. We care about Jordan, whose angry religiosity is alibied by his brutalised features; and we care most of all about Peck, racked first by grief, then by addiction, and finally by the grotesque inexplicability of love itself.

Iñ·rritu's America is scuzzy, scarified and dysfunctional, a mishmash of tract homes, affluent suburbs and a threatening downtown. As a geography anorak, I was interested to discover it was actually shot in Memphis, Tennessee, where a cold snap made the actors exhale smokily even when they weren't - which they mostly were - actually smoking.