Enlightenment

"I control the game, the Doctor's destiny. And soon he will be dead."

When the White Guardian appears uttering a cryptic warning of imminent danger - "the winner takes all," the Doctor is puzzled.  Then the TARDIS materializes on a pseudo-Edwardian sailing ship in the middle of a space race run by the mind-reading Eternals.  The first prize?  Enlightenment - ultimate wisdom to gain one's heart's desire.  But as the Black Guardian's evil mesh draws tight, it looks as though the Doctor may not live to cross the finishing line…

• "Enlightenment" is the fifth story of the 20th anniversary season of Doctor Who.  Each story within this season features the return of one of the Doctor's former adversaries.

• This adventure is the final chapter in a trilogy of stories centering around the Black Guardian's attempts to destroy the Doctor as revenge for thwarting his plans to control the Key to Time.  The first story in this trilogy was "Mawdryn Undead" while the middle part was "Terminus."

• This story also sees the return of the White Guardian, last seen at the beginning of the Key to Time opener "The Ribos Operation."

• It also sees the return of the Black Guardian, who first appeared in "The Armageddon Factor," the final chapter in the Key to Time saga.