The Unthanks–Rachel and Becky, from northeast England–appeared at the Ark a couple of years ago under the name of Rachel Unthank & the Winterset. Their show was terrific. Grim ballads of the region, some of them in a dialect of northeastern England called Geordie, bumped up against the ebullience and humor of a pair of young people who clearly knew they were onto something good. The new Unthanks album is called Here’s the Tender Coming. The title refers to a naval vessel coming to take away a woman’s conscripted partner. The Unthanks were never going to make a happy album, Rachel explains, but Here’s The Tender Coming is hopefully a warmer, calmer shade of sad” than its predecessor, The Bairns.

That may be, but “The Testimony of Patience Kershaw,” drawn from the words of a seventeen-year-old woman who appeared before a British child labor commission in 1842, is harrowing. The gray northern landscape of mines and ships in bad weather hangs over the album, with just a few lighthearted songs for balance. The Unthanks are among the young musicians (Lissa Schneckenburger is another one on our side of the pond) who’ve rediscovered the tragic power of traditional balladry. They also choose the most serious examples from the work of modern songwriters like Ewan MacColl and Lal Waterson.

All this might make an Unthanks concert sound like a downbeat evening, but the musical textures make sure that it’s anything but. The Unthanks, writes British critic Nigel Williamson, are austere but never bleak. The harmonies of the two sisters, full of unexpected turns, is a pleasure in itself, but the real news is the varied group of arrangements by their producer, and Rachel Unthank’s husband, Adrian McNally. They use piano, various stringed instruments, and percussion in a way that attests that, for all the ancient tones of this music, the group members grew up with the electronic textures of modern pop. The voices remain front and center, but the arrangements, which they reproduce in live concerts, both set a mood and help to tell the story. The string quartet in “The Testimony of Patience Kershaw” suggests “Eleanor Rigby” descended into an industrial hell, while the piano and strings of the traditional ballad “Annachie Gordon” intensify the gathering motion of the tale as it moves toward its double deaths.

Despite an occasional squawk of displeasure from the purists about their arrangements, the Unthanks are about the hottest thing going in British folk music these days. It’s a genre that has been underrepresented in southeastern Michigan for some time, and this show should be a rare treat. The Unthanks are coming to the Ark with their own new group of backing musicians on July 6.