More than a decade ago, Anaïs Mitchell was running late for one of her shows. The singer-songwriter, in her 20s at the time, was trying to get from one gig to another and found herself lost. Along the drive, a song lyric popped into her head. "The lines that came were, 'Wait for me I'm coming. In my garters and pearls with what melody did you barter me from the wicked underworld,'" she remembers.