After several members of their family die from arsenic poisoning, Merricat Blackwood lives with her older sister Constance and their ailing uncle Julian in isolation on their New England estate, away from hostile local townspeople. For years, Merricat's magic has seemingly protected the family from harm, but their somewhat peaceful existence is interrupted by the arrival of cousin Charles, who plans to steal the family fortune. Charles' arrival also threatens the dark secret they have been hiding.