Laylora — the Paradise Planet. A world of breath-taking beauty, where the peace-loving inhabitants live in harmony with their environment, Or do they? The Doctor and Rose arrive to find that the once perfect eco-system is showing signs of failing. The Paradise Planet has become a death trap as terrifying creatures from ancient legends appear and stalk the land.

Is there a connection between the human explorers who have crash-landed and the savage monsters? What secret lies at the heart of the natives' ancient ceremonies? And what price might one human have to pay to save the only home he has ever known?

The Doctor and Rose are in a race against time to find a cure for a sick planet.