Mission to the Unknown

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

On the planet Kembel, Space Security Service agent Marc Cory is investigating a recent sighting of a Dalek spaceship. His suspicion that the creatures may have established a base here proves well-founded.

His two companions, Jeff Garvey and Gordon Lowery, both fall victim to the poisonous thorns of Varga plants - ambulatory flora indigenous to the Daleks' home world, Skaro - and he has no choice but to shoot them before they are themselves transformed into Vargas.

Having overheard the Daleks plotting with representatives of the six outer galaxies to overthrow the solar system, Cory records a warning message and prepares to send it into orbit with a rocket launcher. Before he can do so, however, he is discovered and exterminated.

1 out of 87 (1.1%) raters say this story requires a previous story.