The TARDIS lands in the city of Tromesis on Earth – but it’s a world far from the one that the Doctor, Jamie and Zoe recognize. The buildings are ruined, the streets deserted. And against the devastation they see a ghostly mirror image of another place – the city as it was before disaster hit. People vanish here, and huge metal birds attack from the sky. Can the Doctor find the future, in a place that doesn’t have one?