The Doctor and his companions Steven Taylor and Dodo Chaplet arrive some ten million years into the future, on board a generation starship which is carrying the last of humanity away from an Earth that is about to fall into the Sun. However, the cold that Dodo has could prove devastating to these future humans and their servants, the Monoids.

• BBC
• William Hartnell
• Peter Purves
• Jackie Lane
• Eric Elliott
• Inigo Jackson
• Roy Spencer
• Michael Sheard
• Kate Newman