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.

casts

William Hartnell

Peter Purves

Jackie Lane

Michael Sheard

Paul Greenhalgh