Montgomery Bonbon

Many people go their whole lives without noticing anything that is afoot, amiss, or even untoward; without ever experiencing that toe-tingling, stomach-twisting sensation that a mystery is about to unfold. Not Bonnie Montgomery—the world's best detective. Not that anyone (other than Grampa Banks) has heard of her… But they might have heard of the great Montgomery Bonbon, the well-dressed gentleman detective who (apart from the hat and moustache) looks suspiciously like a 10-year-old girl.

When Bonnie Montgomery finally gets a break from cracking cases as her alter-ego, Montgomery Bonbon, something terribly fishy happens the moment she and Grampa Banks arrive on Odde Island for half-term–and it's not just the smell of the harbour. There's been a mysterious death at Leerie Lighthouse, and what everyone assumed was an accident is setting Bonbon's moustache all a-quiver: a sure sign that something is Highly Suspicious.

Bonnie Montgomery (as her case-cracking alter-ego Montgomery Bonbon) has been invited to Adderstone Manor by Fergus Croke, whose prized diamond has gone missing. Croke is a retired master thief who suspects one of his four protégés of the dirty deed – but when everyone is a crook, how does even the great Bonbon know where to begin?