Full Circle

From: http://www.bbc.co.uk/doctorwho/classic/episodeguide

The TARDIS falls through a CVE into E-Space and arrives on the planet Alzarius. There the inhabitants of a crashed Starliner and a group of young rebels called the Outlers, led by a boy named Varsh and including his brother Adric, are being terrorised by a race of Marshmen who emerge from the marshes at a time known as Mistfall.

The Doctor discovers that the Starliner's inhabitants are not the descendants of its original crew, as has been claimed by their leaders the Deciders, but evolved Marshmen. With the Time Lord's help and encouragement, the Starliner is repaired and able to leave the planet.

5 out of 87 (5.7%) raters say this story requires a previous story.