In December of 2021, police in Manchester, New Hampshire made a stunning announcement: a little girl named Harmony Montgomery was missing and no one had seen her for more than two years. Her father, Adam Montgomery, who had recently fought to obtain custody of her, claimed that she was with her biological mother, but police knew that wasn’t true. Where was Harmony? It was Adam’s estranged wife, Kayla Montgomery, who filled in the gaps for authorities that shifted the case from a disappearance to a murder investigation.