When Ottilie's brother Gully goes missing one night, Ottilie sets out to find him -- and soon makes a shocking discovery. Gully has been kidnapped by the Narroway Hunt, a secretive boys-only organisation that hunts savage monsters. Ottilie must disguise herself as a boy if she wants to rescue Gully from the Narroway Hunt. But keeping her true identity a secret is a huge challenge -- especially once she discovers a talent for flying on huge, lion-esque wingerslinks, something only boys are meant to do...