Mulder and Scully aren't just trying in vain to revive a dated franchise. This time, they're in search of a remedy for the spiritual malaise of the West

The X-Files: I Want to Believe has bombed at the box office and disappointed not just film critics but also fans of the iconic TV show. It has also puzzled them. The programme's first big-screen spin-off, ten years ago, was in essence just an inflated episode of the small-screen series. As such, it went down well enough, particularly with aficionados.

This time, however, the brand's originator, Chris Carter, has abandoned the much-loved phantasmagoric world he created, with its ever-ambiguous narratives. In its place, he seems at first sight to be offering no more than a humdrum, body-parts-harvesting serial-killer procedural. Why?

The clue's in the title, or rather the subtitle. It isn't "The Truth is Out There", because Carter has clearly decided that, after all, the truth probably isn't out there and that whether it is or not is no longer the point. Nowadays, there's something more important than tilting at mystery. It's something we've lost sight of, and our salvation depends on getting it back.

The X-Files TV series and it first film spin-off were born of an era of pre-9/11 innocence. Their mission was to titillate the comfortable by conjuring up fanciful perils. Nowadays, we have no more need of fictional chimera: we face real threats a-plenty, ranging from terrorism to economic collapse and climate change. When it comes to dealing with them, however, we're paralysed by a loss of faith. We no longer believe in our leaders, our media, our values, our way of life or even our fellow-citizens. As a result, we are sinking into apathy, cynicism and despair, instead of confronting our demons.

Once his TV series and its associated activities had come to an end, Carter took five years out. He went surfing, learned to fly and climbed mountains. In addition, he says, he came "closer to faith". He seems to have returned to the X-Files destined to reinvent the franchise for a new age in the light of his own epiphany, consciously or otherwise.

In his film, the message is laid on with what at first seems like excessive and unpersuasive zeal. The wintry Virginia landscape is as unforgivingly frozen as our own faithless world. In enforced retirement, Mulder clings stubbornly to his belief that there are more things in heaven and earth than Horatio dreams of. This leads him to endorse the apparently psychic visions of a paedophile priest, who in turn trusts in God's forgiveness. Scully is the sceptic on all of these counts, but puts her faith in untried medical treatments (she's now a doctor) and the God of the Roman Catholics.

By which of this rag-bag of beliefs are we expected to set store, we ask through much of the action. However, as in the best police procedurals, purport awaits the denouement. It turns out that the priest may be a faker who's in on the crime. Or, he may not. Faith doesn't deliver truth. It doesn't necessarily deliver happy outcomes, either. The fate of the child that Scully is treating remains unresolved.

Where we should actually place our faith turns out to be up to us. The Foxes (20th Century and Mulder) not only challenge the claims of truth, but neglect equally to endorse freedom, justice, religion or the American way. The quest for belief itself, however, is now so serious, apparently, that we mustn't squander it on indulgences, like the extra-terrestrials of the TV show. Faith is the key to fighting crucial battles. We cannot simply duck out of these, since the darkness finds us, not we it. Faith is what preserves our ability to press on in the face of the horror of it all. We must therefore embrace it, not scorn it.

Trite? Corny beyond belief? Well, try "Love thy neighbour". Naive or not, The X-Files' message addresses the troubles of our times. There may well be an appetite for it. The tide of Obamamania suggests that lots of people are indeed seeking a repository for faith. Those who pay attention to this film, instead of hankering for the solace that its TV progenitor provided in what is now a faraway age, will be rewarded. They will find that it fulfils the task it has set itself with unusual skill, force and panache. If imparting a moral with intelligence, precision and passion were the test, Gillian Anderson's performance would win her an Oscar.

Show faith. Ignore the critics, and go and see The X-Files. It might do you good. And don't leave as soon as the credits roll, or you'll miss one of the most affecting cinematic scenes of all time.