What if the most terrifying person you know is your ten-year-old sister?  Seventeen-year-old Aussie Che Taylor loves his younger sister, Rosa.  But he's also certain that she's a psychopath - clinically, threateningly, dangerously.  Recenty Rosa has been making trouble, hurting things.  Che is the only one who knows; he's the only one his sister trusts.  Rosa is smart, talented, pretty, and very good and hiding what she is and the manipulation she's capable of.