The Doctor and geologist Nasreen are below ground trying to save Amy and the other hostages, Mo and his son Elliot, from the Silurians, but they end up being captured too.

Back above ground, Nasreen’s colleague Tony begs Alaya, the Silurian they have captured, to cure his sting, but when she refuses, Tony’s daughter Ambrose kills her. Not knowing Alaya is dead, Restac, the military leader of the Silurians demands her release from Rory.

Amy and Nasreen negotiate with Silurian elder Eldane to allow his race to share Earth, but talks end when Rory, Tony and Ambrose arrive with Alaya’s body and a battle with Restac’s forces ensues.

Ambrose reveals she set off a timer to start the drill again and destroy the Silurians. The Time Lord now faces a race against time to stop the drill and get everyone out. Nasreen agrees to end her life’s work and Eldane will allow his race to hibernate for 1000 years and then share the Earth. Tony remains contaminated and stays below ground with Nasreen.

As the others race to the TARDIS, they see the crack in the Earth reappear and the Doctor places his hand in and brings out a cloth containing a shard of the TARDIS’ police box sign.

Restac turns up and blasts Rory with her gun but the Doctor forces a devastated Amy to leave him before the light from the crack touches her and wipes out her existence. The Doctor tells her that Rory still lives in her memory but she appears to have forgotten him.