The Girl in the Lighthouse — Roxane Tepfer Sanford

Not since V.C. Andrews' Flowers in the Attic has there been a family saga so dark and disturbing.
Author Roxane Tepfer Sanford has captured readers from around the world with her best selling Gothic novel The Girl in the Lighthouse.                                   

Arrington, book 1
*first edition

From the time Lillian Arrington was born, she lived an isolated life on a remote lighthouse station with her father Garrett and her young mother Amelia. But Lillian has wishes and dreams far beyond her years. When her father is transferred to a new station, Lillian is anxious to meet the assistant keepers and their two sons, Heath and Ayden. She had never met children her own age, had playmates, or made a friend. Heath, the handsome teenage boy who desires to become a doctor someday, welcomes Lillian. However, his younger brother, Ayden, doesn't like her and she struggles to win him over. Before long, a secret bond between the three is forged and to Lillian's delight, they become close friends. After so many years, Lillian's childhood is beginning to resemble that of a normal girl. No longer is she lonely and isolated from the rest of the world by over-protective parents. Instead, she experiences new adventures, attends school, and falls in love for the first time. However, her glorious days on Jasper Island are short-lived as her beautiful young mother begins a tragic descent into insanity and passes away. Lillian is left in the care of her sinister grandmother Eugenia Arrington, who, since the end of the Civil War, continues to steadfastly hold onto the once glorious Georgia plantation known as Sutton Hall. It is there that the immoral secrets of Lillian's parents are revealed, and she is left to pick up the pieces of her scandalous past, and somehow, find her long way home.     

Arrington series:
The Girl in the Lighthouse
All That is Beautiful
Sacred Intentions, prequel