The Scar - China Mieville (Book 2 in the Bas-Lag Trilogy)

A human cargo bound for servitude in exile... A pirate city hauled across the oceans... A hidden miracle about be revealed... These are the ingredients of an astonishing story. It is the story of a prisoner's journey.

Of the search for the island of a forgotten people, for the most astonishing beast in the seas, and ultimately for a fabled place - a massive wound in reality, a source of unthinkable power and danger.