What are the strange lights in the Strongbergs' barn at night?

Are they related to the recent murders of two Amish men?

Thomas Strongberg's death was said to be accidental. They said he'd fallen off a ladder, but what is the explanation for the second death?

Police have proof that Amish girl, Thea Hersh, is connected to the crime, but Thea refuses to talk to anyone but Ettie Smith. Can Ettie discover the mystery of the strange lights and whether they are related to the murders? Will she find the real killer in time to save Thea?