Not content to be bluegrass wunderkinds, Nickel Creek have steadily edged beyond the genre’s boundaries toward broader terrain. 2005’s Why Should the Fire Die? is their boldest, most risk-taking work yet. On this album, Chris Thile and siblings Sean and Sara Watkins apply their phenomenal instrumental abilities toward a musically challenging, lyrically intriguing batch of tunes. Chris’ expressive singing renders songs like “Can’t Complain” with palpable longing, while Sara’s pristine vocals lend “Best of Luck” and “Tomorrow is a Long Time” a compelling intimacy. The trio veers from the full-on bluegrass charge of “Scotch & Chocolate” to the jazzy sophistication of “Evelyn” effortlessly. Thile’s mandolin virtuosity gives “Stumptown” a luminous sheen. The sonic scope of this album is impressive, ranging from the modern rock muscle of “Helena” to the folk-slanted grace of “Jealous of the Moon.” Why Should the Fire Die? finds Nickel Creek’s creative spark alive and blazing.