Sister Wife Murder follows Chloe (Dia Nash), who after attending church for the first time one Sunday, becomes enamored with her pastor, Caleb (Matthew Daddario). In between secret moments and stolen glances, she falls in love with him only to learn that he’s already married with not one, but two wives. Despite their unorthodox situation, Chloe is overjoyed when he proposes. But after experiencing Caleb’s controlling behavior, she quickly realizes that their love was a far cry from happily-ever-after. Chloe and the other wives, Anna (Ashley Williams) and Margo (Ashley Dulaney), only have each other to depend on and when one of them mysteriously disappears, Chloe fears that she may be next.