The best relationships between singers are symbiotic yet mystical. They bear the demands of the song and revolve around what it needs without discussion. Whether it’s a shared sixth sense or finely tuned intuition, no one has to ask who takes what part. It doesn’t matter anyway — they are of equal importance when two voices nestle seamlessly into a melody, almost imperceptibly gliding across each other when it’s time to switch. It’s not a trick but a sacred dance.

Sisters Shelby Lynne and Allison Moorer, now with twenty-four albums and Grammy, Oscar, and many other kinds of awards and nominations between them, share that kind of transcendent musical bond. It’s as deep, haunting, knowing, and beautiful as the Alabama woods they once called home. Both sang as soon as they could form words, but music is the only language they have ever needed to communicate with and understand each other.