In this episode, the Doctor and his companions finally make it back to space station Nerva, but at a different time. There they encounter the Cybermen. The episode does interesting things with the fact that gold is a weakness of the Cybermen, being capable of destroying them, while in another sense gold is also the weakness of humans. And because of these weaknesses, both seek Voga, the planet of gold. The Cybermen say that they do not subscribe to any theory of morality (in the context an “Armageddon convention” is mentioned). Humans abandon what morals they may claim to subscribe to when it comes to huge amounts of gold. And in the end, the combination of concern for gold and lack of morality leads to downfall. The story is at times convoluted, and perhaps that is because at its heart it is a parable.