The Two Doctors is the fourth serial of the 22nd season of the British science fiction television series Doctor Who, which was first broadcast in three weekly parts on BBC1 from 16 February to 2 March 1985. The serial is set on an alien space station and in and around Seville. In the serial, the alien time traveller the Sixth Doctor (Colin Baker), his former travelling companion Jamie McCrimmon (Frazer Hines) and his current companion Peri Brown (Nicola Bryant) work to save the younger Second Doctor (Patrick Troughton) from the biogeneticist Dastari (Laurence Payne), who intends to steal the knowledge of how to travel in time from the Second Doctor's genetic make-up. This serial marks Troughton's final appearance as the Second Doctor before his death in 1987. Plot The Second Doctor and Jamie McCrimmon land the TARDIS on board Space Station Camera in the Third Zone on a mission for the Time Lords, who have also installed a teleport control on the TARDIS. The Doctor explains that the station is a research facility and that they have to talk to Dastari, the Head of Projects. The Androgum cook Shockeye drugs the meals of the station's scientists. The Doctor tells Dastari that the Time Lords want the time experiments of Kartz and Reimer stopped. The Doctor warns that the distortions from the experiments are on the verge of threatening the fabric of time, but Dastari refuses to order them to cease, accusing the Time Lords of not wanting another race to discover the secrets of time travel. Dastari and the others collapse from the drugged meals. Chessene, an Androgum technologically augmented to mega-genius levels, lowers the station's defences to allow the Sontarans to attack. Jamie sees the Doctor appear to die by the Sontarans before fleeing. In the TARDIS, the Sixth Doctor has a vision of his second incarnation being put to death. Since he is still alive, he is concerned that he may have died in the past and only exists now as a temporal anomaly. He decides to consult his old friend Dastari to see if he can help. The Doctor and Peri arrive on the station and find no signs of life. The station computer demands that the Doctor leave and, when he refuses, tries to kill him and Peri by depressurising the passageway. The Doctor opens a hatch and drags his unconscious companion through to another section.