What makes a cover song great? Is it an unexpected pairing of artist and the material? Is it presenting a song that everyone knows in a brand new light? Is it pulling off a faithful recreation of something that seems impossible? It’s probably a little of all of that, and then some.

“Under The Covers” is a long-running show featuring Jake Armerding, Rose Cousins, Mark Erelli and Zachariah Hickman, that has traditionally played to sold out crowds at Cambridge’s venerable Club Passim for the past 13 years. Every once in awhile, they take it on the road for a few select shows outside of Boston. From Joni Mitchell to C&C Music Factory, Elliott Smith to Def Leppard, Patty Griffin to the Allman Brothers Band, the only thing you can really expect from this show is the unexpected.