AT school, you're taught that every story should have a beginning, middle and end.

The Forgotten certainly has all three, but the final act of Joseph Ruben's thriller, written by Gerald Di Pego, seems to belong to a different film entirely.

The intriguing premise and sustained build-up of tension lead to an outrageous flight of fancy that beggars belief, transporting an intensely human drama into the realms of the fantastical.

Grieving mother Telly Paretta (Moore) is distraught after the loss of her nine-year-old son Sam (Kovaleski) in an aeroplane crash, and is compelled to seek psychiatric help.

Wallowing in grief, Telly is nudged back towards the brink when her psychiatrist Dr Munce (Sinise) and her husband Jim (Edwards) inform her that she never had a son.

There was never an aeroplane crash. Her memories of Sam are the elaborate creation of her delusional mind, possibly fuelled by a miscarriage.

Telly refuses to believe her shrink's outlandish diagnosis, even when all of her photos of Sam vanish and former hockey player Ash Cornell (West), whose daughter died in the same crash, denies ever having had a child.

As she wrestles with these revelations, Telly is placed under surveillance by federal agents.

This attracts the interest of local cop Anne Pope (Woodard), who senses that there may be a germ of truth in what the hysterical mother says.

Then Ash begins to remember, too...

Without giving too much away, even Mulder and Scully would be scratching their heads in disbelief.

It's a real pity, because the ever-excellent Moore delivers a compelling performance as a traumatised parent who begins to question her recall of the past.

Sinise, Edwards and West are wasted, and director Ruben struggles to maintain control of the narrative. But he does create some cheap shocks and thrills in the atmospheric opening act.

DAMON SMITH