"Why are you here? I mean – who are you, exactly?"

An archaeological dig in 1936 unearths relics of another time... And — as the Doctor, Amy and Rory realise — another place. Another planet. But if Enola Porter, noted adventuress, has really found evidence of an alien civilisation, how come she isn't famous? Why has Rory never heard of her? Added to that, since Amy's been travelling with him for a while now, why does she now think the Doctor is from Mars?

As the ancient spaceship reactivates, the Doctor discovers that nothing and no one can be trusted. The things that seem most real could actually be literal fabrications — and very deadly indeed. Who can the Doctor believe when no one is what they seem? And how can he defeat an enemy who can bend matter itself to their will? For the Doctor, Amy and Rory — and all of humanity — the buried secrets of the past are very much a threat to the present...