Up until now Faun Fables, the ever-evolving vehicle for intense Californian banshee Dawn McCarthy, had not released an album since 2006's The Transit Rider. During that time, the genre of mystical folk-infused music that McCarthy encapsulates so majestically (crudely otherwise known as freak-folk) has moved on somewhat, so that it now defines acts as poles apart as, say, Espers, CocoRosie and Bowerbirds. As all this genre-crossing and eclectic posturing has gone on in the last four years, McCarthy has quietly gone about her business, most memorably teaming up with Bonnie 'Prince' Billy on his 2006 album The Letting Go, bringing a darkly profound quality to his already strong predilection for nihilism.

Light Of A Vaster Dark is, in some ways, a back-to-basics record, taking its cue directly from the medieval-influenced, transcendentalism-inspired folk of the late 60s – all of them from Comus to Vashti Bunyan. The Incredible String Band are a particularly relevant touchstone, minus perhaps the wide-eyed psychedelic pastoralism. Faun Fables' fifth album is an irresistible contribution to the oeuvre, and is most refreshing in its deliberate limitations. Instrumentally, the album rarely moves beyond acoustic guitar, strings, wind and primitive percussion.

Such restraint is one of the record's most appealing qualities, as is McCarthy's voice. Huskier and more sonorous than her most obvious comparison, Espers' Meg Baird, McCarthy is what we might call a 'shouter'. That is, one for whom the act of singing is an expression of physical being, rather than something consciously artistic. That's not to say she can't hold a tune – on the wonderful 'Parades' she gracefully reins herself in for what is the closest Faun Fables come to a straightforward, exists-on-its-own-terms pop song.

Those songs on which she lets rip, though, are engrossing. 'On The Open Plains' has a chaotic pagan energy to it thanks to her gleefully demonic vocals. That track, along with the glorious trio of instrumental 'Interludes' on show here, will move many to compare Light Of A Vaster Dark with the soundtrack to The Wicker Man; fair enough, but McCarthy's scholarship goes back much further - indeed, there are moments here that even put one in mind of Gregorian or early music.

McCarthy refers to herself as a 'songteller', which reflects the album's dramatic structure, and further aligns her with the Incredible String Band, whose Robin Williamson traverses the country these days peddling himself as just that. From the album's first words of 'It began with the cold…' sung by McCarthy on the title track, we are dealing with a strange psychedelic narrative that takes in the seasons, the elements and the supernatural. It's all very abstract of course, though occasional bursts of theatrical coherence do occur, such as on the album's best song, 'Housekeeper'.

In case it hasn't been made clear, there is a strong Celtic influence at work here, and perhaps it is on this side of the Atlantic that McCarthy's closest musical kin can be found. Manchester's Jane Weaver released The Fallen By Watchbird earlier this year, an unpretentious album comparable in its shimmering, meditative take on psych-folk. It would be nice if Faun Fables didn't wait four years before making another record - but then again, if that's how long it takes to put together something as magical as this, McCarthy should take all the time she needs.