In the conclusion of the 14-episode continuity "The Trial of a Time Lord," the Doctor (Colin Baker) discovers the real reason that he has been put on trial for violating the Laws of Time. But his troubles are far from over, as he and his chief accuser, the Valeyard (Michael Jayston) embark upon a harrowing virtual-reality tour of the Matrix. The climax finds the Doctor locked in mortal combat with an evil incarnation of himself. Written by Pip and Jane Baker and originally telecast on December 6, 1986, this episode, officially known as Doctor Who: The Ultimate Foe, Episode 2, represented not only the final chapter of Doctor Who's 23rd season, but also Colin Baker's farewell appearance as the Doctor. ~ Hal Erickson, Rovi