In the tradition of legends Rhiannon Giddens and Gillian Welch, Anna & Elizabeth mined the old-timey traditions to put grit into their soulful, calling-down-the-gods ballads and reels. Multi-instrumentalists with yearning, hair-raising harmonies, these young musicians’ mastery of the Appalachian mountain style of music has been heralded as some of the best since Bill Monroe.