Gillian Flynn fans rejoice — this Summer YA release will give you major chills. Claudia's best friend, Monday, has vanished, but no on else seems to be worried about her whereabouts or finding the missing girl. Claudia knows that Monday wouldn't leave her to face the horrors of high school alone, and as she begins her search, it becomes clear that both Monday's mother and sister are keeping a big secret. Can Claudia come to her friend's rescue or is there something more sinister going on that will threaten to take her as well?