Mary Grace Sudduth

Mary Grace Sudduth lives on her family plantation in south Georgia. Beautiful and intelligent, she goes to a medical college in Georgia, and goes to Utah to complete her residency. There she meets Heber Smith, a dermatologist. He woos her and they marry. This upsets her parents, mostly because Mary Grace must marry in the temple in Salt Lake City and not being Mormons, her parents cannot attend.

After the wedding, Heber's personality changes and he becomes a tyrant. Then, thinking Heber is having an affair, a private investigator finds Heber is a polygamist with three other wives and six children. Mary Grace tries to make the best of this, but when Heber decides to take a fifth wife and the woman is to be the daughter of Mary Grace's best friend, Mary Grace kills Heber with a muscle relaxant.

Then, Mary Grace kills her best friend's husband because he is intent on his daughter living in a polygamist relationship. Her best friend is actually the one who gives her husband the muscle relaxant. Then Ellen, the best friend, has a friend who is in a terrible relationship and whose husband is molesting his three daughters.

Hyrum Smith learns the sheriff's office is investigating Mary Grace and entices her to leave town with him. He takes her to a polygamist colony in the high Mexican mountains. There she meets Brad Nelson, a returned soldier with severe PTSD. They fall in love, but Brad owes his well-being to the prophet of the community who has promised Hyrum he can come to the colony and kill Mary Grace, for "Blood Atonement," a Mormon dictate that says when a person commits a crime so serious, the only way they can achieve salvation is to have their blood spilled on the ground.

Mary Grace's parents hire Theo Reed, a retired chief of detectives, and Aiden O'Brian, a forensic psychiatrist. Their investigation determines Mary Grace is in Mexico. The FBI and the Mexican Federal police get involved, as does a Special Prosecutor. Hyrum Smith and his wife are arrested, the prophet is arrested for his involvement in Mary Grace's murder and fraud against the government, and the colony is searched and evidence is found.

Brad tries to get away, but in the chase with officers, he is terribly burned and hospitalized. Mary Grace's body is found, and she is buried at her favorite spot on the plantation. Eventually, Mary Grace's parents decide to have Brad live and work at the plantation. Brad is so badly disfigured he would have little chance. All this time, Mary Grace's mother has felt her daughter is dead but doing fine on the other side, as she is visited by a strange butterfly.