The reptilian Silurians are the former rulers of Earth. A drilling project awakens them – and now they want their planet back!
The Doctor (Matt Smith) and his companions, Amy Pond (Karen Gillan) and Rory Williams (Arthur Darvill), land in Wales in 2020, where a drilling operation headed by Nasreen Chaudhry (Meera Syal) is drilling deep into the earth and disrupting a civilisation of Silurians who dwell beneath the earth. The Silurians cause holes to open in the earth, one of which consumes Amy. The Doctor and Rory capture one Silurian, Alaya (Neve McIntosh), and the Doctor instructs Rory and a local family to not harm Alaya, as it could spark a war. He then takes Nasreen in the TARDIS to the Silurian civilisation to rescue Amy and a local boy.