It seems almost obligatory these days to climax any thriller with an almighty twist designed to bring about much forehead slapping and jaw dropping from audience members.

Next week's John Travolta in Basic is a film that will keep you guessing until the very end.

And there is a similar - and more effective - set up in this week's Identity, a film with more twists and turns than a German grand prix circuit.

Events take place on a dark night in the Nevada desert, where the mother of all storms is raging.

Different sets of circumstances lure different sets of people to a lonely and isolated motel. With flood water closing many of the roads in the vicinity, the situation becomes increasingly desperate for many of the guests.

A woman needs urgent medical treatment after being run over by a car. A cop must find a secure spot to keep the dangerous prisoner he is transferring. A young couple is strangely far from happy after tying the knot in Las Vegas. And an actress is desperately trying to get in touch with her people in Hollywood.

But their problems are nothing compared to the horror that is about to be brought upon them in the form of a sadistic killer who is slaying the guests one by one.

It's a good job there is a regular cop (Liotta) and a former cop (Cusack) on hand to track down the murderer and clear up the mystery.

Remember, though, that this is a film in which all is most definitely not what it seems, not least the characters who populate this dense and dark murder mystery. It's a psychological thriller, with the emphasis very much on the psychological.

This fact is emphasised by the action at the motel being punctuated by events elsewhere which sees an attempt to impose a stay of execution on a killer just hours away from the gas chamber.

How does this have a bearing on the mystery at the motel? Well, it's a very big part of the story and pay close attention, because clues are dotted about which hint at the surprises that lay in wait.

There is more than a hint of Alfred Hitchcock in this film - the motel certainly resembles the one in Psycho - and the build up of suspense is a direct influence from the master of this genre. And whodunnit fans may feel director James Mangold has read a few Agatha Christie mysteries in his time.

Otherwise Mangold and screenwriter Michael Cooney have constructed a taut and original thriller that almost - but not entirely - ties up all the loose ends to satisfactory effect.

At first, the big twist, when it does come, may seem like a cop out on the lines of "Oh, it was all a dream." But when the events and characters are reassessed in light of the revelation, it makes some sort of sense.

Identity is not quite as clever as it thinks it is, and it relies rather too heavily on cliches and stereotypes to make it a wholly satisfying thriller.

But there is enough atmosphere and tension to sustain interest to the final minutes.