What is the overall conflict in all four books?

Ethan Wate is a teenager who lives in the small town of Gatlin, South Carolina, with his father and their housekeeper Amma, who is also Ethan's primary caregiver. Ethan's mother died not too long ago and he and his father are still struggling. Amma is a Seer and charms around the house are a part of Ethan's life that he seldom dares question because Amma is so serious about them. Ethan has been dreaming of a girl. In the dream, he's trying to save her but she slips away from him.