A literal sister act, classically-trained sibs Kathryn, Annika, Fiona and Petra von Grey banded together. The Atlanta-based quartet is known for "four-part harmonies, poetic lyrics and indelible melodies." They've already landed residency shows and opening slots for the likes of Sarah McLachlan, Company of Thieves and Lindsey Stirling. Earlier this year, they performed their haunting hit, "Coming for You," on "Late Show With David Letterman." All that, and they're still in their teens. They make a stop at Isis Restaurant and Music Hall on Saturday, Dec. 7, at 9 p.m. $12/$15. isisasheville.com.