The last time we saw Fox Mulder and Dana Scully was back in 2002, huddled together and waiting for the end. The final alien invasion of Earth was scheduled for 2012, a decade ahead, and humankind was doomed.

Six years later, and all of our lives have moved on. But have – and, indeed, how could – theirs? Well, all thoughts of impending ET apocalypse seem to have vanished from both characters’ and film-makers’ minds, at least for now. Carter’s attempt to sidestep the convolutions of the series’ increasingly unwieldy and incoherent ‘mythology’ means that this belated visit to a franchise that ultimately collapsed under the weight of its own backstory is a standalone affair in the tradition of many of The X-Files’s best episodes; trouble is, this isn’t really one of them.

We begin with the reassuringly familiar device of ticker-tape typescript telling us where and when we are – in this case, a bitterly cold and snowbound West Virginia, all blizzards and drifts – and a typical pre-credits teaser that plays through two, perhaps related, events in violent counterpoint: an attack on a woman in her garage and a line of FBI agents spread out across the snows in search of… something. They follow a demented-looking, white-haired figure until he falls to his knees, crying: “It’s here!” His frantic digging reveals a dismembered human arm.

At this point we’d normally cut to the titles, and then re-emerge in Mulder’s office, but times have changed. Scully has returned to medicine and is working in a Catholic hospital, where she’s currently faced with a difficult decision about a terminally ill child; Mulder has become an FT clipster, complete with crazy Biblical beard, and spends his days scissoring weird stories from the dailies. It emerges, too, that they have been partners in life instead of work for the past six years. Now, against both of their better judgements, the odd couple are drawn out of retirement and into one last case when it turns out the woman who was attacked is a missing FBI agent and that the only lead the Bureau has is the wild-haired Father Joe (Billy Connolly), a disgraced Catholic priest and paedophile who, as Scully forthrightly puts it, “buggered 27 altar boys”. With this sort of background, should his apparent ‘gift’ be trusted? Mulder tends to think so, while Scully is both repulsed by Father Joe’s deeds and conflicted about how God – or something else – could possibly work through such a man.

Given that Carter and Co. managed to keep the lid on spoilers so successfully and for so long, I won’t reveal any more of the storyline; suffice to say that there are no aliens or rumours of aliens, no conspiracies and no monsters, except of the all too human variety.

All of which makes this a funny sort of a comeback for the TV show that pretty well defined the Nineties, particularly for anyone of a fortean bent. It’s way too soon for it to exploit the sort of nostalgia that has transformed Dr Who from camp BBC pariah to family-friendly Golden Goose and far too late to build on whatever momentum the series still possessed as it limped toward its ultimately unsatisfying conclusion. What we’re left with is something that feels curiously out of joint with the times, neither cynical CGI cash cow nor joyous return to the glory days of the series at its peak. Instead – and in striking contrast to the franchise’s first big screen outing a decade ago – this is a low budget and almost wilfully low key affair, eschewing thrills, spills and, for the most part, even chills, in favour of a modest, muted and melancholic meditation on faith and the mysterious workings of God. As interesting and unusual as this might be for a genre movie, it’s also perverse in the extreme. After all, this is a movie, for cripes sake, not Answer to bloody Job, and it’s hard to see either devotees of the series or curious newcomers being satisfied by what boils down to a padded-out TV episode with a script full of holes that manages to be both dour and daft at the same time. It even looks and plays like a sub-par two-parter from the series’ early days; and, as was often the case, the set-up is promising, the denouement almost embarrassingly disappointing. Really, after all the months of secrecy, the film needed to tell a bigger and better story than this one if it was to avoid leaving fans with a nagging sense of disappointment and newbies wondering what on Earth all the fuss was ever about.

But there are consolations along the way, particularly the pleasure one feels on seeing Duchovny and Anderson stepping into the skins of these much-loved characters once again (even if the film, in typically contrary fashion, insists on keeping them apart for long stretches). They’re older and wearier than the Mulder and Scully we remember (wouldn’t you be?), but that’s part of the film’s point. Duchovny offers flashes of the old deadpan humour and laid-back charm, while Anderson is almost painfully luminous, reminding this reviewer, at least, that, Carter aside, it’s only the great Terence Davis who seems to have detected the chaste, magical quality in her face that harks backs to the golden age of Hollywood and makes the rest of today’s Tinseltown actresses look like a bunch of two-bit tramps. Connolly, too, is surprisingly good as the dishevelled and disreputable Father Joe, creating a good deal of sympathy for a difficult character, although none of the other roles – goodies or baddies – are sufficiently developed to offer much scope to the actors.

Early box-office and some awful reviews suggest that this could be the last we see of Mulder and Scully; and even with the best will in the world, it’s hard not to argue that Carter should have torn up his script, pulled out the stops, and gone for broke here, as it would be a real shame if this unassuming effort, ill-equipped to deal with any real weight of expectation, proved their swansong and scuppered plans for a third instalment. My advice: go and see it anyway, as we’ll still need someone to save us from the impending horrors of 2012.