The first time the voice kept Cece Ogbuji awake was on a school night in the fall. Cece, who was fifteen, was having a busy week of classes and theatre practice and homework. She needed to sleep. So why was her mother talking so loudly in the next room? “Oh, my God, O.K., so, Sapphire,” her mom said, “let me just tell you this.” Cece knew that the voice didn’t belong to her sister, Zi, who ...