The Hungry Earth (1)

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 below. Amy Pond discovers there's nowhere to run when you can't even trust the ground at your feet.