Tilly's Secret

When Tillemina Shaw turns up at the Carnival after disappearing eight years before, she discovers that it’s very different from when she was a child. For a start, her teenage crush Cal is now the head chef, and he’s still angry with her for leaving without saying goodbye.
Everyone except Cal welcomes her back with open arms, pleased she’s returned. Only problem is that Cal’s right to be suspicious â€" she’s secretly spying for their enemies, and what she learns will be used to destroy the Carnival once and for all.

This book is a novella, and is the third book in the Magic Carnival series.