With intriguing subject matter, a solid cast and a writer with a good track record, what is most puzzling about 'Shelter' is how this supernatural horror manages to move from the sublime to the ridiculous so quickly.

Dr Cara Jessup (Moore), a renowned sceptic in the field of multiple personality disorder and devoutly religious, is introduced by her father Dr Harding (DeMunn) to Adam (Rhys Meyers), a particularly troubling case. Adam, it seems, is the real deal. In a wheelchair when his other personality David is present, but then able to stand as Adam; colour-blind one minute, but able to pass complicated tests the next, his appears to be one of the most severe cases ever seen. Things get even stranger when Jessup gets the results of two x-rays of Adam/David which seem to confirm they are two separate people. Baffled, she looks to dig deeper into Adam, and/or David's, past.

From these hopeful beginnings the plot and script unfortunately jump right off the deep end. Jessup's one-woman investigative team discovers that Adam's other personality, David, was murdered horrifically more than 20 years previously. But when she and David's real mother confront Adam it seems to confirm that the murdered teenager is indeed speaking through Adam. Soon other personalities appear and Jessup begins to fear for her own life, her family and friends.

Coming from the producers of 'The Ring' and the writer of 'Identity' - which also centred around multiple personalities - 'Shelter' promises much in its opening half but then gets hopelessly lost as it combines religion, science and some sort of strange voodoo. Directed by Swedish duo Måns Mårlind and Bjorn Stein, there is plenty of suspense to be found early on, with Moore and a very creepy Jonathan Rhys Meyers both turning in decent performances.

Often misunderstood and misrepresented on film, multiple personalities and delusions are two of the more fascinating areas of psychiatry. Where as Michael Cooney's script for 'Identity' stayed grounded in some sort of realism, resulting in a rewarding pay-off, 'Shelter' goes the other route, becoming all the more impossible, even comical, as it progresses. When the mystery is finally explained it demands a leap of faith which even the biggest of horror fans will find hard to countenance.

There are plenty of scares along the way, some more formulaic than others, but with an ending that's pure hokum, 'Shelter' carries off the impressive feat of making 'The X-Files' look like a respected scientific journal.

Gimme 'Shelter'? No thanks.

Padraic Geoghegan