2009. Cahalan woke up alone in a strange hospital room, strapped to her bed, under guard, and unable to move or speak. Her medical records chronicled a monthlong hospital stay of which she had no memory at all. Neurologist Souhel Najjar recognized the symptoms of a newly discovered autoimmune disorder in which the body attacks the brain, a disease now thought to be tied to both schizophrenia and autism, and perhaps the root of "demonic possessions" throughout history. This is the account of one woman's struggle to recapture her identity and to rediscover herself among the fragments left behind.