Why Should the Fire Die? is Nickel Creek's first album without Alison Krauss in the producer's chair, and on it, the trio's genre-expanding acoustic music has shifted even farther away from its bluegrass origins. The opening "When in Rome" perfectly encapsulates the aggressive approach the band favors, and features poetic lyrics far more obtuse than those of most groups with similar roots. The disc's first half stays rooted in a fairly conventional folk mode, with a lovely cover of Bob Dylan's "Tomorrow Is a Long Time" (one of the few solo vocal turns from fiddler Sara Watkins) and "Jealous of the Moon" (cowritten with the Jayhawks' Gary Louris) obvious highlights.

But the album gradually grows darker. The songs take unexpected twists that are challenging and unconventional, while still emphasizing those angelic vocal harmonies that float and sting. Chris Thile's peppy instrumental "Stumptown" leads into the menacing "Best of Luck," with its edgy minor-key chorus echoed by Watkins's deceptively sweet voice spitting out lyrics of an obsessive high-school love affair gone wrong. And the drums of "Helena," one of the group's most radical compositions, bring out Nickel Creek's inner Coldplay. Not a complete break with their bluegrass beginnings, Why Should the Fire Die? is certainly the trio's boldest and most creative album, albeit one that might not appeal to their earliest fans. --Hal Horowitz