School should have been the safest place... For Lizzie Riley, switching her eight-year-old son Tom to the local academy school marks a fresh start, post-divorce. With its excellent reputation and outstanding results, Lizzie knows it'll be a safe space away from home.

But there's something strange happening at school. Parents are forbidden from entering the grounds and inside, there are bars across the classroom windows. Why is Tom coming home exhausted, unable to remember anything about his day? What are the strange marks on his arm? And when Lizzie tries to question the other children, why do they seem afraid to talk? Tom's new school might seem picture-perfect.

But sometimes appearances can be deceiving...