Mexican director Alejandro Gonzalez Inarritu made a huge splash with his debut feature, the tough-minded, Academy Award-nominated Amores Perros. Despite a great cast - Sean Penn, Benicio Del Toro, Naomi Watts - his first English-language film falls victim to the sophomore jinx. A serious minded, but unremittingly grim, visually ugly and thematically uninteresting work, it uses a fractured narrative to hide the fact that it's plot - a man receives a heart transplant, seeks out the wife of the donor and falls for her - has been done before as a fluffy Hollywood romantic comedy starring David Duchovny called Return to Me.

Sean Penn must have a penchant for movies in which revenge is visited (or nearly so) on the man who has run over and killed an innocent. His second picture as director, The Crossing Guard, hinged on that construct, and it is a major part of 21 Grams (the title of which does NOT refer to a heaping stash of cocaine - although drugs play a role - but to the amount of body weight ostensibly lost by at the moment of death).

Penn plays Paul, a critically ill mathematician in dire need of a heart transplant. When born-again ex-con Jack (a pudgy, but still gorgeous Del Toro) accidentally runs over and kills a man and his two young daughters, Paul receives the dead man's heart. Setting out to find out just whose heart he has leads him to make contact with the donor's wife Cristina (the excellent Naomi Watts), a woman who, her life having been destroyed, has been awash in drugs since the accident. A needy romance blooms - much to the chagrin of Paul's wife Mary (French former ingenue Charlotte Gainsbourg, daughter of Serge). As Paul and Cristina grow closer, they decide to kill Jack, the man responsible for the destruction of her family.

Although it seems to want to be a heartfelt exploration of grief, mortality, revenge and redemption, 21 Grams comes across as more of a cold, calculated academic exercise in editing techniques. Beginning with a shot of Paul sitting on a bed watching a sleeping Cristina, the film moves back and forth in time, slowly sketching in the details of what exactly is going on. At times reminiscent of Memento - with none of the frisson of discovery that that film generated - 21 Grams is at times exasperating because of its determination to be profound.

And, for the life of me, I cannot understand why director Inarritu and cinematographer Rodrigo Prieto chose to use a colour palette that renders the actors (two of which - Watts and Del Toro - are objectively beautiful) and the world they live in as pallid, desaturated, butt-ugly people and places. I'm not asking for gloss, but isn't this supposed to be a story, ultimately, of redemption? Not if you look at the images.