Serial: 5M  Episode Nos. 526, 527, 528, 529, 530, and 531. All episodes not completed. Title: Shada

The infamous uncompleted, untransmitted story.  Retired Time Lord Prof. Chronotis of Cambridge asks the Doctor to return a powerful book to Gallifrey for him.  This book is required, however, by a mind-stealing scientist known as Skagra, who requires it to gain entry to the Time Lords' prison planet Shada, where the great criminal Salyavin is imprisoned.  With Salyavin's mind added to his collection, Skagra hopes to infect everyone in the universe with one universal mind: his own.

This is the last story to feature David Brierley as the Voice of K9.

starring Tom Baker as Doctor Who, Lalla Ward as Romana, and David Brierley as the Voice of K9. Written by Douglas Adams, Produced by Graham Williams, and Directed by Pennant Roberts.

Originally scheduled to be transmitted from 19 January 1980 to 23 February 1980 on BBC1.