The Pyramid at the End of the World

Written by Steven Moffat and Peter Harness

"The end of your life… has already begun. There is a last place you will ever go. The last door you will ever walk through. A last sight you will ever see. And every step you ever take… is moving you closer. The end of the world is a billion, billion tiny moments. And somewhere unnoticed, in silence or in darkness… it has already begun."

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?