Seventeen-year-old Milly is continually bullied by Amelia Norris. Day in and day out, Amelia torments Milly and even threatens to hurt her, but Milly can't tell anyone—not a soul. Why? Because Amelia is Milly—they both co-exist as one in the same body.

Milly is so disconnected from her past that she feels compelled to find out what truly happened to her when her parents were still alive. After a mysterious fire, she and Grandpa George move into Aunt Rachel's Victorian home where Milly then begins to unravel puzzling clues to her family history. Through dreams and scattered memories, Milly journals her story, trying to cope by putting the shattered pieces back together, all the while resisting her inner demon.

But Amelia won't go down easily, and is determined to cut Milly out of the real world—literally. After Milly stumbles across Aunt Rachel's notebook, she begins to wonder who her real family is. Little by little, Milly assembles the pieces of her shattered past and begins to feel like everything she thought to be true is one big lie.