Location: Cwmtaff, Wales Date: 2020 Enemies: Silurians In 2020, the most ambitious drilling project in history is under way. Dr Nasreen Chaudry and her team have reached 21 kilometers into the Earth's crust - but something is stirring far belo... (more)w. Amy Pond discovers there's nowhere to run when you can't even trust the ground at your feet.

Meera Syal, Stephen Moore