Esta é Boa Montanha por Robert Reed. Foi em Melhor Ficção Científica do Ano: Vinte e Quarta Colecção Anual
The world is made of living island, which travel around the ocean, until they eventually hit the Continent, and stick to it. Thus, the Continent gets ever bigger. Public transport is done by worm (as in, inside the living worm, which even has windows), and everybody has mockmen slaves, who seem to be like humans but bred to be barely intelligent enough to perform tasks. Now, as the Continent gets bigger and bigger, it traps rising bubbles of methane gas rising from the ocean under it, which leads to explosive blow-outs, which can devastate whole islands at a time, as they're basically made of living wood. Currently, these blow-outs get progressively worse, and the whole Continent is going up in flames. On the last worm, a group of travellers is racing ahead of the flames, trying to reach the coast and a ship to outlying islands.