Imagine a 2022 version of the rustic harmony and song-splurge electricity of Bob Dylan and the Band’s  Basement Tapes, and you’ll have a pretty decent notion of what Big Thief are up to on their fifth album. Dragon New Warm Mountain I Believe In You is a 20-song double-LP in which the much-beloved Brooklyn band chases its indie-folk sound all over the backyard in search of new wrinkles and revelations. “Change, like the wind/Like the water, like skin,” singer Adrianne Lenker offers, signaling the album’s mutable intentions at its deliberately lovely outset.

Lenker’s personal, pastoral songwriting and fragile, down-home warble are always at the center of Big Thief’s music. But after starting out as a rangy, poetically hard-bitten guitar band on their 2016 debut Masterpiece, they’ve pulled off the neat trick of becoming at once more rootsy and more cosmic, earthier but somehow less earthbound, suggesting Bright Eyes and Jenny Lewis fans tapping into the old, weird America as the blueprint for their dream-folk epiphanies.

The band hit a stunning creative peak with U.F.O.F. and Two Hands, two equally excellent albums released six months apart in 2019. Dragon New Warm Mountain I Believe In You might have benefited from a similar release program, but as its dubious title suggests, an over-abundance of whimsical discovery is part of the mission here. “It’s music. It’s music!,” Lenker sings, setting the tone on “Time Escaping,” a vaulting rush of percussive anarchy, lithe melody, and ecstatic word-salad revelation. (According to the band, she was addressing her dog, who’d run into the studio during the song’s recording.)

That headlong, try-everything ambition is all over the place here. The warm, rollicking, “Spud Infinity” breaks off for an almost comically long Jew’s-harp jam. The almost impossibly pretty jangle-core revery “No Reason” comes with a bell-booted flute solo. (John Barleycorn must live!) The title track gathers itself hazily, like a mystical vision coming into soft focus, with Lenker’s diaphanous whispers refracted through webs of ghostly acoustic playing. “Little Things” ambles athletically for nearly six minutes, as Lenker sings about falling dangerously in love in New York City as brackish guitar static and relentlessly tumbling drums mirror the scary rush of romantic obsession.

Big Thief revel in the old-fashioned, mythic, and arcane, but their music is at its best when they blur eras and historical map-points. With a drum track that suggests hail on a distant tin roof, the gauzily distorted “Blurred View” lands somewhere between Nineties trip-hop and an Alan Lomax field recording.  On “Certainty,” the band shambles winsomely and Lenker sets a comfy scene: “Sit on the phone, watch TV/Romance, action, mystery,” evoking Dylan and the Band finishing up a day’s work at Big Pink and kicking back with a little Netflix and Wordle. The acoustic waltz “Dried Roses,” a sweet old-timey evocation of domesticity, is followed a couple songs later by “Wake Me Up to Drive,” with sad-Eighties guitars and a drum machine bauble beat that makes it feel a little like Lenker’s version of “Within Your Reach” by her fellow Minnesota natives the Replacements.

An inspired afterthought like that might not have made the album if it was limited to the normal 12 or 13 songs. Dragon New Warm Mountain I Believe In You can feel redundant at points, and might be a little much to wade through unless you already roll waist-deep with the Big Thief experience. Yet the cumulative sense of the open-ended, accidental, communal, and casual is worth any slowish spots along the way. This is a band that deserves the time you lend it.