With other bands Tweeting and gut-pouring, there’s something startling about this London trio’s impenetrability. They create mood songs as discrete units, each as bulletproof — or smudgeproof — as the band itself. Credit Sian Ahern, a singer with Nico’s presence and complexion, minus the contralto. Here, Ahern’s glassy, emotionless voice acts as a guide, snaking through tribal percussion and grain-silo howls, until the high-hat shimmer of “Salt Water” comes to a violent, distorted close. It’s an ambiguous ending that makes the journey all the more fascinating.