Will and Alice Harding, and their seven-year-old son Toby, have just moved to a new house in the countryside. Hoping for a fresh start, Will's and Alice's past hides dark secrets that are just waiting to emerge. Soon, Toby begins to change; his voice, his appearance, his demeanor. Finally accepting that something is seriously wrong with their son - something traditional medicine can't help with - Will and Alice turn to folk magic for help. But can they figure out what the powerful, mysterious force is that plagues their son... and how to defeat it?