The Demon Headmaster

I'm read a book called The Demon Headmaster, it is about a girl called Dinah, she is an orfan, when one day a family fostered her. So she started to go to the same school as the two kids that lived with her, Lloyd and Harvey. When her first day of scholl starts, she met the headmaster, he was very strange and it seemed that the school was controles, because everybody was perfectly organised. What do YOU think it will happen to the kids? i recomend this book for people that likes mistery and suspense!!