In the near future, The Doctor and Clara arrive on a decrepit shuttle making a suicide mission to the Moon. Crashing on the lunar surface, they find a mining base full of eviscerated corpses, spider-like creatures scuttling about in the dark, and a terrible dilemma.

When Osgood is kidnapped by a rogue gang of Zygons, the Doctor, Clara and Unit must scatter across the world in a bid to set her free. But will they reach her in time, and can they stop an uprising before it is too late?

With UNIT neutralised, only the Doctor stands in the way of the Zygons.

An “ancient” pyramid appears overnight. Every clock in the world begins counting down to the Earth's destruction. Three opposing armies lie ready to annihilate each other. An alien race stands ready to offer humanity a deal that could save them, but also enslave them. It's a terrifying race against time to save the world. Will the Doctor be forced to accept their help?