A moral questioned is being asked, Alaya the Silurian that attacked and injured Tony, is being held prisoner up on the surface, Tony and Ambrose his daughter have reason to kill her, as does Rory because of Amy being taken. The Doctor and Nasreen have travelled down to the base of The Silurians, to seek the missing people. Having discovered there is a full Silurian society, they are imprisoned. Naturally The Silurian on Earth pushes somebody's buttons, and the Doctor's lost his bargaining tool.
I'd have to praise the little guy that played Elliot, possibly the most interesting character of the lot. Kid did a great job. I'd also like to praise Nia Roberts, little dubious in Part 1, but she was very good in this better scripted episode.
Second best bit, Nasreen and Amy discussing the future of Earth and Silurians with the Silurian leader. A great scene, really well played out. However they saved the best til last, the crack in the wall rears its ugly head once again, and the worst thing happens... It makes the opening of Part 1 seem relevant.
Silurian culture is very interesting, I praise Chris Chibnall for creating an interesting Silurian Society, there are different factions, different ideas and infighting.
I wasn't entirely in love with Part 1, I was fairly bored for most of it, and same for the best part of this one too. Watching it I keep thinking 'we've been here before, nothing original on show. The action scenes are pretty good, but overall it's just unsatisfying, it was too long over two episodes. 6/10