An authoritarian father and subservient mother keep their three adult children entirely isolated within a walled suburban compound. The parents construct a surreal, false world through fabricated vocabulary and fear, telling their children they can only leave once they lose a dogtooth. To fulfill their son's sexual needs, the father regularly brings home an outside security guard, Christina. However, when Christina introduces smuggled Hollywood videotapes to the elder daughter, the psychological illusion collapses, leading to severe punishment, forced incestuous pairings, and a desperate escape attempt.