Ep 7. The Silurians, Episode 6

The Doctor and Liz Shaw return to the underground research center to continue their investigation of the mysterious power loss. When they discover a hidden cave system, they come face to face with a tribe of prehistoric reptilian humanoids known as the Silurians. The Doctor tries to establish peaceful communication between them and the humans of the research center, but tensions rise as misunderstandings and suspicions grow on both sides. Meanwhile, a militant faction of humans led by Major Baker decides to take matters into their own hands and launch an attack against the Silurians, putting everyone in danger. As the situation escalates, the Doctor must use all his skills and diplomacy to prevent an all-out war and uncover the truth behind the power loss.