Looking for Barbara, the Doctor, Ian and Susan learn that they have been exposed to lethal doses of radiation. The travellers are confronted by the city's inhabitants - the Daleks! Show more
Ian and Barbara join a Thal expedition that will penetrate the Dalek city from the unguarded mountains behind it. Their journey is a dangerous one, and not all will survive.
The Doctor and Susan are once again taken prisoner by the Daleks. In the mountains, Ian, Barbara and the Thals must negotiate a vast chasm to reach the city.
