|'The Roots of Evil'
by Eoin Colfer
Eleven Doctors, eleven months, eleven stories: a year-long celebration of Doctor Who! The most exciting names in children's fiction each create their own unique adventure about the time-travelling Time Lord.
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.
*Featuring the Fourth Doctor, Leela and K-9 MkI
*A Puffin Books 'Doctor Who' novel
*This novel was part of a series of ebooks published by Puffin over the course of 'Doctor Who's 50th Anniversary year; each book featured a different incarnation of the Doctor, and was billed as a 're-imagining' of the character; I am therefore not considering them as canon
*The story was later released in paperback form in November 2013, in the anthology 'Doctor Who: 11 Doctors, 11 stories':