Over the course of their previous two albums, New York foursome Big Thief pruned their meaty alt-rock back into mellow indie. UFOF sees them pare things down further still, in a collection of gentle folk that seems dazed by its own exquisite beauty. Sometimes, the results bring to mind a sugar-coated Elliott Smith: acutely lovely melodies are layered over beds of softly hypnotic guitar, the finger-picked figures gratifyingly soporific in their apparent capacity to continue for ever. At others, the band channel a kind of diluted, Americana-tinged pop, buoyed along by its own breathy charm.

Yet UFOF is also careful to temper its prettiness and prevent it from becoming cloying: unsurprisingly for a record that references alien objects in its title (the F stands for “friend”), this is an album that is awash with uneasy wonder. Vocalist Adrianne Lenker paints portraits of people and places with a woozy impressionism that could make even the most banal of domestic scenes sound like a close encounter with aliens. To unsettle things further, she warps her voice, pitching up from its default – bewitchingly fine to the point of frailty – into a shrill, shuddering vibrato (Orange), or descending into a cold, throaty croon (Betsy), with a subtlety that renders its shapeshifting form all the more eerie. Occasionally, the production lends a hand – Jenni features a spectral false start, a brief burst of song replaced by whining feedback like the uncertain first glimpse of a horror-movie ghoul, while on the title track, Lenker’s voice is chopped and distorted until she embodies the extra-terrestrial life form the lyrics allude to.

Now and then, the band delve back into their previous, less rarefied styles: during the finale of opener Contact, which flowers into a grunge nightmare fashioned from beefy riffs and screaming feedback, or on Jenni’s swelling, shoegaze chorus. Those diversions create moments of gut-wrenching contrast, making hackneyed rock tropes feel surprising again – proof that with this softening of their sound, Big Thief have alighted upon something that packs a real punch.