Miles grandmother has Parkinson s. Inspired by the squirrels in the garden, Miles and his grandmother decide to write a book to raise money for a Parkinson s charity. The result is a mystery story, in which the main characters are based on Miles and his grandmother. Sorrel the squirrel and her friend George take on the task of discovering why Felicity, the girl next door, has been left with her eccentric aunt, with no explanation from her parents. The mystery becomes even more curious when Sorrel spots another girl with Felicity s mother. Who is this girl? And why are Felicity s parents keeping her a secret? Will Felicity be even more unhappy when she discovers the truth? All profit from the sale of this book will be donated to Parkinson's research.