Mogwai's first foray into film soundtracking came with Zidane: A 21st Century Portrait back in 2006, and it immediately threw up a couple of difficult questions. Firstly, why hadn't they ever scored a film before? Their uncanny knack for tapping into their audience's emotions wordlessly, for evoking a passionate response through epic soundscapes, was well-established. Beyond that, why did it take something as esoteric, at least in film terms, as a ninety-minute documentary (and I use that word loosely) about a footballing icon? There's any number of cinematic scenarios for which music as atmospheric as Mogwai's would be a perfect fit.

Not counting a collaboration with Kronos Quartet on the soundtrack for Darren Aronofsky's The Fountain, the first post-Zidane scoring opportunity that they've actually taken up is for Les Revenants (currently airing on British television as The Returned), a supernatural French drama far more intelligent than your average zombie flick; in a rural settlement that's drenched in a brand of small-town claustrophobia that immediately recalls Twin Peaks, dead people begin to show up alive and well, bringing a host of paranormal phenomena with them.

I don't want to come over as disparaging where Zidane is concerned; both film and soundtrack are superb, as last week's live performances at the Manchester International Festival duly confirmed, but I, at least on paper, seems like a far more logical match for a band as adept at playing around with mood and feeling as Mogwai.

What's particularly interesting is the fact that the series had yet to start shooting when the producers asked the band to get started on writing the score; they wanted to set the musical mood early, in order to inspire the thematic development of the show as production progressed. With such a scarce foundation on which to build - scripts for early episodes were all the band had access to - you immediately wonder how they're supposed to react. Is it going to be a kitchen sink job or something more restrained?

The answer, we now know, is the latter; Mogwai are notorious for the awesome, often overpowering cacophonies of noise they can conjure up with a few guitars both on record and on stage, but there's not much of that on Les Revenants. Instead, they've kept things relatively quiet, and it contributes to the atmosphere of the show in fairly straightforward fashion. There's plenty of piano; on 'Kill Jester', it steadily ascends, underpinned by mournful strings, whilst 'Portugal' drowns the keys in a familiar wall of guitar noise; it's fainter than it might be on a normal Mogwai record, but it's there, and it simmers towards that scratchy, static fade out that they do so well.

Instrumentally, they've expanded in places - the relentless synth buzz of 'Modern' is a case in point - and it's clear that not every track is supposed to fit inside some kind of straightforward, sinister box; 'Whisky Time', with its minimalist bass-and-piano approach, seems primarily concerned with contemplation, and 'Special N' channels the band's uplifting side, using guitars melodically, and leaving the reverb behind.

The funny thing about this soundtrack is that, even taken as independent from the television show, it still has the intended effect; it's music designed to make you feel as if something's not quite right, that's supposed to inspire unease and emotional discomfort in the listener. That effect will be accentuated, I imagine, for anybody already familiar with Mogwai's work, if only because you so often spend the quiet sections of their songs waiting for the loud part to come crashing in, but that doesn't happen on Les Revenants; ultimately, everything just slowly fizzes away. There's no hellish maelstrom of guitars akin to 'Mogwai Fear Satan', or screeching riffs puncturing near-silence as on 'Like Herod'.

Like so many of the characters on the show, Mogwai have returned as a different iteration of themselves; Les Revenants isn't quite what we've come to expect from them, but then that's the whole point.