Everyone thinks that Sophie is an orphan. True, there were no other recorded female survivors from the shipwreck that left baby Sophie floating in the English Channel in a cello case, but Sophie remembers seeing her mother wave for help. Her guardian tells her it is almost impossible that her mother is still alive--but "almost impossible" means "still possible." And you should never ignore a possible.

So when the Welfare Agency writes to her guardian, threatening to send Sophie to an orphanage, they takes matters into their own hands and flee to Paris to look for Sophie's mother, starting with the only clue they have--the address of the cello maker.

Evading the French authorities, she meets Matteo and his network of rooftoppers--urchins who live in the hidden spaces above the city. Together they scour the city in a search for Sophie's mother--but can they find her before Sophie is caught and sent back to London? Or, more importantly, before she loses hope?

Phillip Pullman, author of the His Dark Materials series, calls Rooftoppers "the work of a writer with an utterly distinctive voice and a wild imagination."