Life with Shepherd is the only life Selah has ever known. Their self-sufficient community possesses no modern technology, and is hidden away in the woods, far from modern civilization. He is the group's guardian, teacher, and lover. Each of the many female members of the group is either his wife or daughter. Selah is pure in faith, but also dangerously headstrong. She was raised as a daughter of Shepherd, but it is only a matter of time before she also stands to become a wife. As an encounter with the authorities forces the women and Shepherd to build a new Eden further inland, Selah increasingly doubts her faith, and has strange, bloody visions. The onset of puberty brings with it harsh new rituals, and her first shocking glimpse of what happens to Shepherd's women as they age.
This film provides examples of:
- Abusive Parents: Shepherd is initially of the psychological variety, conditioning his daughters to be slavishly devoted to him, but graduates to physical as the film goes on, beating, molesting and nearly drowning them at various points to retain his control.
- Bittersweet Ending: The younger members of the Flock break free from Shepherd's control and kill him, allowing them to forge their own paths, but their mothers have all been killed.
- Broken Pedestal: The daughters lose all their reverence for Shepherd after finding out he had killed their mothers.
- Cult: "The Flock" is essentially this.
- Death by Childbirth:
- How Selah's mother died. Or at least, how she thought her mother died.
- One of the women ends up conceiving during the journey. The trauma of the delivery, combined with the lack of sufficient medical assistance, results in her passing away as a result.
- Domestic Abuse: Shepherd towards all of his wives, but Sarah, the "cursed wife", receives the worst of his treatment.
- First Period Panic: Selah has one once she starts her period, as women are viewed as impure after menstruation.
- Missing Mom: Selah's mother died shortly after she was born. As revealed by Sarah, she fell sick shortly after giving birth, but Shepherd refused to take her to the hospital, resulting in her death.
- Parental Incest: Shepherd starts eyeing his teenage daughter Selah to become his new wife as she comes of age. Upon reaching their new home, Shepherd sexually assaults Selah at night. The following day, he kills the older wives with the intention of replacing them with his daughters.
- Patricide: The daughters mob and kill Shepherd upon discovering he had killed their mothers so they could become his new wives.
- Villainous Incest: Shepherd seeks to force his daughters, particularly Selah, to become his wives once they come of age.
- Wife Husbandry: Shepherd raises all the daughters with the intention of making them his wives once they come of age.
- Would Hurt a Child: Shepherd orders for his male newborn to be abandoned to die, as only "one ram in a flock". It's implied to not be the first time.
