(Photo: Kai Regan/Courtesy of Touch and Go Records)

Bianca and Sierra Casady are in debunking mode. It’s been three years now since their debut album as CocoRosie, La Maison de Mon Rêve, set the indie world on full-blown freak alert, and their image has gotten slightly out of hand. They’ve done photo shoots reclining in clawed bathtubs and caressing one another in bed. They’ve flaunted tear-tattooed eyes, vertical hair, and Native American fringe over basketball shorts. They’ve recorded songs about invented fauna, like “bisounours,” and looped kitten mewing onto their creaky, homemade sonic collages. They’ve been captured on film in the heat of their recording technique: Bianca fingering the piano with one hand and holding a portable cassette player in the other while Sierra, perched on a bicycle, strums a guitar and warbles into a microphone strung around her neck. They’ve volunteered information about their strange past, like how their nomadic artist mother forbade TV and radio and their Cherokee-shaman dad dragged them around the desert each summer while he munched peyote. They’ve claimed kinship with fairies. “See my haircut right now?” demands Sierra in The Eternal Children, a Danish TV documentary, pointing to her jagged jet-black bangs. “I didn’t do that. I have a couple fairies in my house that are there just to drive me nuts, and they cut my hair when I sleep … You’ll see my hair all over the pillow, and scissors and stuff. It’s like, Dammit! They got me again!”

All of this makes quite an impression. By the time I dial them in their Paris lair—they recently relocated from Brooklyn—my imagination is in overdrive. I’m picturing gaslit rooms strewn with tree branches and toy instruments. I’m picturing a creature, half-female, half-faun, clopping daintily toward the cell phone and depressing the talk button with a cloven hoof. “Hello?” it murmurs.

“Bianca?” I ask.

“No. Almost,” says Sierra.

I remind her about that fairies thing. “Is it true?” I ask.

It’s as if I’m the child and she doesn’t want to spoil something for me. “Just recently, I think I found out Bianca did it,” she says. “But I don’t know if I’ve gotten the whole truth yet. It’s still up in the air.”

Now’s a good time for CocoRosie to dip a toe into the real world. Their third album, The Adventures of Ghosthorse and Stillborn, is too good to languish on the fringe. Plenty of weirdnesses remain—“Japan” starts with a harp melody, fuses into a bass-driven rhythm, and then bursts open into an off-kilter aria—but compared with the rest of the freak-folk genre, the production is cleaner and more solid, the overall feel less wiggy and hand-hewn. Some songs, in their ingenious appropriation of hip-hop beats and surrealist wordplay, recall Beck’s groundbreaking nineties album Odelay; elsewhere, a sense of backyard clatter evokes Tom Waits. As with previous work, CocoRosie recorded the basic tracks in the south of France, in “our nice barn with candles and owls and nightlife all around us,” Bianca says. But they finished up in Iceland with producer Valgeir Sigurðsson, a studio co-hort of Björk’s and Sigur Rós’s. Outside help was welcome: “The small sounds, the very subtle, distant delicate sounds—she brought those forward,” says Sierra. “Massaging the frequencies and bringing things out that couldn’t have been heard otherwise—for instance, a small sound of a horse moaning in the background.” But not too welcome. “We were interested in a technical hand and a system to hear everything on,” Bianca elaborates. “We’re not looking for aesthetics from somebody else.”

But what really makes Ghosthorse and Stillborn worthy of a jump for joy is CocoRosie’s transformation from self-conscious oddity into an actual songwriting force. “Werewolf” is a harrowing piecing-together of summers with father, in which grown-up sexual promiscuity bleeds into fear-filled recollections of a domineering adult:

You left me broke down beggin’ for change
Had to catch a ride with a man who’s
deranged
He had your hands and my father’s face
Another Western vampire different
time same place.

Bianca willingly cops to the album’s autobiographical quality. “My father came up a lot on this record,” she says. “I do feel a sense of working through something without having to work through it with him. Whether he hears it or not really doesn’t make a difference. There was something healing about it. It brought me personally into the music in a way that I wasn’t before.”

I tell her I have wild notions about what those summers were like. “They were wild,” she says. “They were arduous. We never stayed in hotels. He’d drive at night while we slept in the car. We’d go on long hikes without much food. My dad was on this constant vision quest.”