AU Author. The Divide is flooded. The Homunculus has fled upriver into the Hanging Mountains, pursued by Sal and his companions in a ship of bone. There, among balloon cities and ghostly fog forests, they are caught in a three-way war between intelligent apes, humans and animated stone statues. They stumble across the truth: that the Homunculus is the cause of the Cataclysm, the mysterious apocalypse that destroyed the old world thousands of years ago. The closer they come to the heart of the mountains, the clearer it becomes that something else is stirring there, and that every assumption they have made might be wrong.