The thief knot : a Greenglass House story
(Book)

Marzana and her best friend, Nialla, are bored. In a city where normal rules don't apply, it seems that adventure should be everywhere, yet nothing exciting ever happens to them. Nothing, that is, until Marzana's parents are recruited to help solve a kidnapping that makes no sense. This could be the excitement Marzana and Nialla have been looking for - if they can crack the case without getting caught meddling. They gather a group of kid detectives with special skills-including a magician, a master of subterfuge, and the ghost of a ship captain's daughter-to join them in a heart-pounding race against the clock to beat the deadline for a ransom that's impossible to pay. But in a place where nothing and no one are what they appear to be, from the architecture that changes overnight, to the substitute math teacher, to Marzana's own parents-it soon becomes clear that even the kidnapping might not be what it seems. There's more to unravel than just the crime, and truths to be discovered about their families and themselves-if only the young detectives can puzzle it all out in time.--taken from book jacket.