The following version of the book was used to create this study guide: Bohjalian, Chris. Hour of the Witch. Penguin Random House, New York, NY, 2021. Kindle AZW file.

Mary Deerfield is married to Thomas, a miller seen as an important man in Boston in 1662. Though Thomas provides Mary with the necessities at home, he is cruel and demanding. She concocts stories to explain bruises and is amazed at Thomas's audacity to lie about Mary's clumsiness. Mary feels their servant, Catherine, adores Thomas in an inappropriate way. Mary cannot understand this, considering the lack of kindness Thomas shows Catherine. Thomas is a widower with a grown daughter, Peregrine, who is married to Jonathan Cooke and has two daughters.

Mary's parents are James and Priscilla Burden, who arrived in Boston from England to do the Lord's work and to expand James's expansive shipping business. James and Priscilla give Mary a set of three-pronged forks one day, part of an incoming shipment of goods from England. Mary is horrified because everyone sees the three-pronged forks as instruments of the Devil. Her parents assure her the utensils are gaining popularity in England and predict they will soon be accepted in Boston. When Mary and Thomas are in a heated argument, Thomas stabs Mary in the back of the hand with a fork, and she decides she can no longer stand his cruelty. She goes to her parents who welcome her back into their home and seem to support her decision to sue Thomas for divorce.

The court proceedings put Mary's reputation on trial. Testimony put Mary's morals into question, including a moment when a handsome young man named Henry was about to kiss Mary. By the end of the court hearing, Mary is sent back to Thomas's home. She discovers her parents, a magistrate, and Thomas made this plan to protect her from burgeoning rumors that Mary is possessed by the Devil. Mary moves back, but Thomas's continued cruelty make her decide to poison him. She changes her mind at the last moment and decides to fake her own suicide and leave Boston with Henry. Before they can set that plan in motion, Mary is tried as a witch. On the day of her trial, she suddenly realizes clues she had overlooked indicating that Peregrine hates her father and has been trying to kill him. On the night before she is to be hanged, Peregrine arranges for Mary to “escape” from jail. Peregrine reveals that Thomas killed her mother and abused Peregrine as a child. She confirms she had tried to kill him. As Peregrine leads Mary toward the wharf where Henry is waiting, they encounter Thomas, who is drunk, with an equally drunk friend. Thomas and the friend beat Peregrine. Mary kills Thomas while Peregrine kills Thomas's friend. In the Epilogue, Mary and Henry are back in England. They are living on family property near Mary's brother. Mary has a young daughter.