The TARDIS brings the Doctor and Mary Shelley to the continent of Zelonia, on the frontier world Draxine where, many moons ago, the twin citystates of Garrak and Stronghaven bore testament to mankinds colonial spirit. That was before the sinister death cult of Garraks President Harmon took hold - and Garrak annihilated itself, utterly, in an apocalyptic explosion. Before the bones of Garraks dead came back to life, and its skeletal citizens began marching, marching, marching on Stronghaven itself. But what do they want, this army of death? And can anything stop them?