Once upon a time, Robert Plant was the living incarnation of great god Dionysus, and he and his fellow gods of the holy quartet Led Zeppelin delivered Bacchic revels and priapic ecstasies to their followers in the bleak epoch of the dark god Nixon. But when drummer John Bonham died of overindulgence, the spirit of Zeppelin died with him—and so did Plant’s career as Dionysus.

Since then, Plant has reincarnated himself as an R&B crooner, a world music traveler, and, most recently and successfully, as American roots music’s elder voice on Raising Sand, his 2008 disc with Allison Krauss produced by T-Bone Burnett. But the spirit of Dionysus still hovered behind Plant—­until he reached back to before Zeppelin ruled the earth with the release in 2010 of Band of Joy.

Named for Plant’s band prior to his apotheosis, Band of Joy shares salient features with Raising Sand. Patty Griffin takes on Krauss’s role as femme fatale, Buddy Miller takes on Burnett’s roles as guitarist and coproducer, and Darrell Scott takes on most of the other roles on a host of string instruments, while Byron House and Marco Giovino play supporting roles on bass and drums. But the basic tone of Band of Joy is darker and messier than that of Raising Sand, with more grunge in the mix than Burnett would likely have allowed.

All of the twelve songs are covers, save for one original by Plant and Miller. Three are traditional numbers arranged by Plant and Miller, while the rest range from Los Lobos’ “Angel Dance” to Richard Thompson’s “House of Cards” and Townes Van Zandt’s “Harm’s Swift Way,” with stops along the way for Barbara Lynn’s “You Can’t Buy My Love” and Milton Mapes’s “The Only Sound That Matters,” plus “Silver Rider” and “Monkey” by Low, Duluth’s own slowcore kings.

Some of Band of Joy is fun. “You Can’t Buy My Love” and “Angel Dance” have irresistible tunes and lighter-than-air grooves. Some is haunting. “Silver Rider” and “Monkey” are cinematic tone poems full of dread and despair. Some is pretentious. “Satan, Your Kingdom Must Come Down” has an arrangement so solemn it’s silly, and “Even This Shall Pass Away” has an arrangement so insipid it’s silly.

For me, Band of Joy doesn’t quite cohere as an album, nor does the band quite cohere into a band. This isn’t to say that the musicianship isn’t first-rate, but as a unit they lack focus and force. But Plant took them on the road last fall in Europe and they’ll be touring America this winter, with a show in Ann Arbor’s Hill Auditorium on January 21. Four months of playing together could make them truly a band of joy.