In a cramped dressing room in the bowels of Brighton Dome the husband-and-wife duo the Handsome Family, aka Brett and Rennie Sparks, are reflecting on why they abandoned their Chicago home three years ago for the dustier climes of Albuquerque, New Mexico. For Brett, a thick set, former born-again Baptist who once tried to write his own bible, it was to be nearer his family in Texas and "to escape the insanity of the city. You go on the road and you come back, and you're twice as crazy as you were on tour. Albuquerque is a good place to decompress."
For Rennie, a black-clad acid casualty and writer of arguably the most darkly sublime lyrics in country music, it was more a case of wanting to fit in.
"New Mexico's full of UFO crackpots, so I'm in good company," she says. "I can have long conversations with people about Bigfoot and they don't think I'm weird at all. There are a lot of hippies there but there's also a lot of nefarious military stuff going on which makes it kind of interesting. Every once in a while you get some really strange planes flying overhead that just don't look right."
Conversation with Brett and Rennie can take some bizarre twists and turns. Over the course of an hour, we cover such broad subjects as spiritualism, the Salem witch trials, the miracle of microwave ovens and the " invisible ethers that are all around that we can never perceive but only see by their effect on us". Their live show in the evening is no different, with Rennie talking at length in between songs about how US Wal-Marts have got so big that pine forests have sprung up between the aisles, her husband's fear of daylight, and the deer she imagines sitting in the audience.
Next week the Handsome Family release their seventh album, Last Days of Wonder. As with its predecessors, death and darkness pervade nearly every song. Human skulls lie in limestone caves, eccentric inventors die alone in hotel rooms, young lovers court silently in graveyards. Woodland creatures, an enduring Handsome Family motif, also make frequent appearances, often at the end of a huntsman's rifle. "Hunter Green" is a chilling number in which the protagonist shoots into the woods at a white deer and ends up killing his lover instead. The tale continues when the "next night I rowed upon the waves to catch a leaping fish/But on the hook my lover's heart I pulled from the briny depths".
At the heart of the Handsome Family is Rennie's storytelling that pays elegant homage to the narrative traditions of folk music. Certainly, such vivid writing is a lost art in a pop scene dominated by grunting hip-hop stars and scantily clad R&B divas.
"Most people's agenda in their lyrics is to say: 'I'm sexy, now pay attention.' I guess you can say that without having a narrative going on," she reflects. Instead, Rennie marries macabre themes such as murder and suicide with the everyday minutiae of life. Played live, it borders on performance poetry, with Rennie's words gathering greater shape amid her husband's stripped-down compositions and soulful baritone vocals.
Rather than look to records for inspiration, Rennie takes her ideas from reference books, novels and, more recently, barmy late-night radio shows in which people air conspiracy theories and play recordings of the ghosts living in their basements.
"Tesla's Hotel Room", a song on the new album about the Croatian inventor and pioneer of modern electrical engineering Nikola Tesla, who died alone and destitute, touches on one such conspiracy theory about his plans to build a death ray capable of shattering the planet.
"There's this idea that now, in Alaska, the government is using his plans to build this thing called the Harp Project, which is this vibratory force that can destroy things at long distances, and is making the whales beach themselves," says Rennie. "The whales are definitely beaching themselves, though you imagine that that's more to do with water levels. But I love this kind of stuff."
Brett and Rennie met when they were at university in New York - Rennie was studying philosophy, while Brett divided his time between a masters degree in pre-14th-century classical music and playing in a band. From there the pair moved to Chicago where Rennie got a series of secretarial jobs and Brett stayed at home writing songs and playing guitar.
After years of playing rockabilly, Brett had returned to the music of his youth - folk and old-time country - and had begun listening to the Carter Family, Hank Williams and Jimmie Rodgers. "Some of the greatest songwriters have used country music as a framework for their songs - the Beatles, the Rolling Stones, Neil Young," he says. "There's an essential reason for that. It's very primordial. When I finally started listening to it again, it was like a homecoming. It really hit me over the head."
Meanwhile, Rennie was sending off short stories and poems to publishers, though her work was deemed too dark for publication. Eventually, Brett suggested she condense her stories into songs. By this time, Rennie was working as a copywriter for a lingerie catalogue and had mastered the art of writing economically.
"I had to write these one-sentence pitches and sell a product in this little tiny space. I would say stuff like: 'Lace, the world's most romantic fabric, now in easy-care polyester!' The more I did it, the easier it got and it really helped me to write concisely. I think I learned more doing that than anything."
Rennie's lyrics secured the Handsome Family's leap from the merely good to the extraordinary. And, little by little, they've been catching on. In 2003, the US rock critic Griel Marcus wrote an essay praising "words that in their everyday surrealism have no parallel in contemporary writing" and pronounced them "the Beatles of the folk world". That same year Ringo Starr declared himself a fan and the former Catatonia singer Cerys Matthews covered their ode to suicide "Weightless Again" on her solo album Cockahoop. More recently they came to the attention of television viewers when they appeared in the BBC Arena film Searching for the Wrong-Eyed Jesus.
While they are hardly about to storm the charts - they are first to acknowledge their music is too unfashionable and their lyrics too rarefied for mainstream consumption - they are content. After 15 years, they no longer have to take jobs in between tours. Theirs is a simple operation and they have no use for roadies or managers. "There isn't all that much to manage," says Rennie. "We're not children, we can get ourselves out of bed in the morning, manage our finances and work out what needs to be done. Trust me, it's not that hard."
"It's not good to be famous," adds Brett. "It's a very silly pursuit. You get less time to yourself and less time to work on the music. Everyone wants to go to the next level but I say: 'Screw the next level.' It would be nice to have a driver, and maybe even some new instruments, but if it doesn't happen, I can live with it."
'Last Days of Wonder' out on Monday on Loose. The Handsome Family tour to 3 June (www.handsomefamily.com)