In order to complete his plan to bring himself back to full size after his accident with his tissue compression eliminator, The Master tries to destroy the Doctor. Turlough makes a decision and tells the Doctor why he was exiled to Earth.

Sharez Jek and his androids save the Doctor and Peri from execution when he rescues them. Then he takes a shine to Peri and wants her with him forever. Later the Doctor and Peri find out they are dying from Spectrox Toxemia, having been poisoned when they handled the Spectrox nest upon first entering the cave system.