Consisting mostly of sagely chosen cover tunes, the album finds Plant and Krauss bringing their warm-but-eerie harmonies to everything from Townes Van Zandt's nihilistic folk poetry ("Nothin'") to the crumbled beauty of latter-day Tom Waits ("Trampled Rose"). Determined not to rest on their laurels or cater to expectations, the 59-year-old icon and his junior partner craft a subtle and intriguing sound built on their shared love of folk forms and gift for interpretation, bringing to light esoteric gems by late Byrds visionary Gene Clark and the Everly Brothers along the way as well.