The Time Lord Omega reveals himself to the third Doctor along with plans for vengeance against his own kind.
Quest roles:
William Hartnell(The Doctor), Patrick Troughton(The Doctor), Nicholas Courtney(Brig. Lethbridge-Stewart), John Levene(RSM Benton), Roy Purcell(President of the Council), Graham Leaman(Time Lord), Stephen Thorne(Kastrian Eldrad), Rex Robinson(Dr. Carter), Laurie Webb(Mr. Ollis)