A young British woman named Sinaloa (Sophie Reid) comes to Texas to find Merle (Allison Tolman, Fargo), her half-sister by way of their dead country-musician father. It doesn't take long for Sinaloa to charm her way into Merle's life. Her singing awakens something in Merle and erases some of the lingering doubts about their shared bloodline. But an all-too-familiar chaos comes with it, which soon starts to unravel Merle's stable world—her job, her upcoming marriage, and an already tense relationship with her mother, Patricia (JoBeth Williams). And although the family music legacy brought this stranger to town, darker motives are woven into the songs she sings, showing glimpses of a violent rage that's been building for years.