The Roots of Evil (short story)

 was the fourth Puffin eshort released to celebrate the 50th anniversary of Doctor Who.

Publisher's summary
When the Fourth Doctor takes Leela to visit an immense tree space station known as the Heligan Structure, little do they know that the tree has been asleep for centuries, dreaming of vengeance against a man in a blue box ... As the tree awakes, the Time Lord and his companion soon discover why they are such unwelcome guests.

Plot
to be added

Characters

 * Fourth Doctor
 * Leela

Continuity

 * Leela remembers seeing the steel hives of the Sun Makers of Pluto. (TV: The Sun Makers)