Postmodern Jukebox has become well known for rearranging pop songs in an old-fashioned way, but for the first time, they've taken on a metal track, and they did something pretty remarkable with it.
With 15-year-old singer Caroline Baran fronting the group, they performed Metallica's "Nothing Else Matters" in a jazz style.
It's not too shabby, considering the song came out in 1991, more than a decade before Baran was born.