The Slippery Slope: A Series of Unfortunate Events, Book 10, by Lemony Snicket, illustrations by Brett Helquist

Book 10 of the series finds the unlucky Baudelaire children separated: Sunny has been kidnapped by Count Olaf and his henchfolk, while Violet and Klaus have been left for dead. But thanks to a chance meeting with another person who is supposed to have died, they find themselves on the path towards some answers about the real nature of VFD and its connection to their family and the events following the fire which took the lives of their parents. After ten books it's difficult to maintain the madcap lugubriousness, but Snicket does the smart thing by allowing events to develop and characters to change, and to give enough hints as to what's really happening to keep the reader (even one twenty years beyond the recommended reading age) interested.