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.” “I’m all ears, Roschelle,” a female voice replied. Cece knew that the voice didn’t belong to her sister, Zi, who was just a year older than she was. Sometimes their mom’s best friend came over late at night, but the voice wasn’t hers, either. “What’s got you so fired up?” the voice continued. “Lay it on me!” Cece got out of bed, put on a pair of fuzzy pink slippers, and stomped to her mother’s office. Roschelle spent most of her days there, usually in a swivel chair, looking at a pair of computer monitors. But Cece found her in a nightgown, turned away from her screens, facing a small gray orb on the floor. “What is it, Roschelle?” the orb asked.…