For some, M Night Shyamalan's career has been a case of diminishing returns ever since 2000's 'Unbreakable' - maybe even since 'The Sixth Sense'. Others have followed his work with great enthusiasm, rating him as a director who has set himself apart from the pack with his choice of stories and subjects. Now comes 'Lady in the Water', Shyamalan's most divisive film yet.

Cleveland Heep (Giamatti) is the superintendent at a suburban apartment complex called The Cove. Heep keeps himself to himself, tries to cater for the residents' every whim and generally just get on with a life which has dealt him a massive amount of tragedy.

Heep's soul is rousted out of its slumber, however, by something which at first seems as innocuous as a resident using the pool after hours. Investigating one night, Heep almost drowns but is rescued by a mysterious young woman called Story (Howard) and wakes up in his apartment to hear her fantastic tale.

Story tells Heep that she is a 'narf', a member of a nymph-like race whose destiny is tied to those of the residents of The Cove. With a vicious creature waiting for her in the grass around the apartments, Story needs Heep's help to get home - and the others in The Cove will also have a role to play.

Based on a bedtime story Shyamalan wrote for his children, 'Lady in the Water' is guaranteed to wind cynics up no end but there are others who will be smitten and return to it again and again. It's not a thriller or a ghost story: it's a quirky fairytale about people realising their true purpose in life - with a subtext about American society if you want to read that far into it.

No-one does put upon better than Giamatti and his performance as the unlikely hero drives this film even when it looks like it's going to become too slight for its own good. Howard is good if unremarkable in the Story role and while some of the supporting characters seem a little too close to cut-outs, this film has a charm that will make its fans all feel something special. For the fate of The Cove's resident grumpy film critic alone it's probably worth paying into.

Where Shyamalan loses many points here is the ending, which is both an anti-climax and far too abrupt. By that stage you'll have either lost your patience completely or will be desperate for the film not to end. However much a flop it turns out to be, 'Lady in the Water' is guaranteed to find a very enthusiastic younger audience, make others roll back the years in their own minds and have a life long, long after its cinema obituary has been written.

Harry Guerin