Planet of Fire is the fifth serial of the 21st season in the British science fiction television series Doctor Who, which was first broadcast in four twice-weekly parts on BBC1 from 23 February to 2 March 1984. In the serial, the Doctor's old enemy, the renegade Time Lord the Master (Anthony Ainley), plots to use the volcanic gases on the planet Sarn to renew his body after accidentally shrinking himself in an experiment. Peter Davison's penultimate serial as the Doctor, it marks the departure of Mark Strickson as Vislor Turlough (who makes a brief reappearance in a dream sequence at the end of Davison's final story) and introduces Nicola Bryant as Peri Brown. It is also the second and final appearance of the shapeshifting robot Kamelion, who is played at various points throughout the serial by Gerald Flood, Dallas Adams, and Ainley. Plot On the desert world of Sarn, robed natives worship the fire god Logar and follow the Chief Elder, Timanov, who demands obedience. Dissenters are known as Unbelievers and two of them, Amyand and Roskal, cause unrest when they claim to have ventured to the top of the sacred fire mountain but not found Logar. One of the Sarns, Malkon, is known as the Chosen One because of the unusual double triangle symbol burnt into his skin: he is also unusual for having been found as a baby on the slopes of the sacred fire mountain. The same triangle symbol is found on a metal artefact uncovered in an archaeological dig in Lanzarote overseen by Professor Howard Foster. His stepdaughter Peri Brown is bored with the dig and wants to go travelling in Morocco and when he seeks to prevent this she steals the strange artefact and tries to swim for freedom. Fortunately for her the TARDIS has landed nearby—responding to a distress call sent by the strange artefact—and Turlough sees her drowning and rescues her. Going through her possessions as she recovers he finds the artefact and acknowledges the same triangle symbol is burnt into his own flesh. The Fifth Doctor returns to the TARDIS after attempting to find the source of the signal emitted by the artefact, and the ship dematerialises, seemingly on its own. It arrives on Sarn and the Doctor and Turlough set off to explore. The android Kamelion has meanwhile made mental contact with its old controller, the Master, who attempts to assert