The Ark (Doctor Who)

''The Ark'' is the sixth serial of the third season of the British science fiction television series ''Doctor Who'', which was first broadcast in four weekly parts from 5 to 26 March 1966.

The serial is set at least ten million years in the future. In the first two episodes the time traveller the First Doctor (William Hartnell) and his travelling companions Steven Taylor (Peter Purves) and Dodo Chaplet (Jackie Lane) arrive on a generation ship, which Dodo names "the Ark". The Doctor searches for a cure for a fever that has spread across the human and Monoid races on board the ship, who have no immunity to it. The last two episodes are set 700 years later, and involve the Doctor, Steven and Dodo working with the Refusian race to stop the Monoids from wiping out the last of humanity with a bomb. The story constitutes Dodo's first journey as a companion to the Doctor. Provided by Wikipedia