Planet of Fire - Plot

Plot

On the desert world of Sarn, robed natives worship the fire god Logar and follow the Chief Elder, Timanov, who demands obedience. Those who dissent 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 Perpugilliam (usually called '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 Doctor returns to the TARDIS after attempting to triangulate the source of the signal being emitted by the artefact, and the ship dematerialises, seemingly on its own. It soon arrives on Sarn and the Doctor and Turlough set off to explore.

The Doctor's other companion, the android Kamelion, has meanwhile made mental contact with its old controller, the Master, who attempts to assert his control and change Kamelion's appearance from that of Howard. Kamelion tries to warn Peri of the Master but the Time Lord succeeds in gaining control. She flees the TARDIS with the creature in pursuit as the rumblings of the volcanoes of Sarn gather ferocity.

In the Sarn colony Timanov has damned the Unbelievers to be sacrificed to appease Logar and stop the tremors. They flee to a secret base in the mountains which is filled with seismological apparatus and which the Doctor and Turlough stumble across. The Doctor informs the Unbelievers that the tunnels, which have been their refuge, are volcanic vents which will soon fill with molten lava. It is also established that Turlough is of the same race as those who colonised the planet, and when the indigenous people see his Misos Triangle, they greet him as a second Chosen One. Turlough realises Malkon may be his brother and becomes even more worried when Peri turns up and mentions the Master.

Another important figure in Sarn mythology is the Outsider, a promised prophet, and the Master/Kamelion fulfils this role admirably. He convinces Timanov of the appropriateness of harsh action and when the Doctor arrives with the Unbelievers they are all seized for burning. However, Malkon and Peri arrive shortly afterward and end this assault, though not before Malkon has been injured. Turlough is aghast when he finds his relative has been shot and the Doctor presses him for as much information as he has on the strange circumstances of Sarn. It seems it is a long abandoned Trion colony planet, and that Turlough, a Trion, suspects some of his family were sent here after a revolution against the hereditary leading clans of his homeworld. He supposes his father died in a crash but that Malkon survived, while he himself was sent in exile to Brendan Public School in England, overseen by a Trion agent masquerading as a solicitor in Chancery Lane.

The Master/Kamelion has meanwhile seized Peri and uses her to transport a black box into the control room of his TARDIS. It contains a miniaturised Master – the real thing – who has been transformed by a disastrous experiment with his trademark Tissue Compression Eliminator (TCE) weapon. The Master thus re-established the psychic link with Kamelion to gain the power of movement and has manoeuvred the robot to Sarn so that he can take advantage of the restorative powers of the numismaton gas within the fire mountain.

Turlough realises the imminent volcanic bursts will destroy the Sarn colony, so nobly uses a functioning communication unit to get in touch with Trion and plead for a rescue ship to evacuate the planet. In so doing, he abandons his own freedom. Acting on a message from the Doctor, Turlough programs the TARDIS to rescue the Doctor and Peri from the gas control room, forgoing a chance to stay aboard and escape from the military arriving from his homeworld. He finds out that a general amnesty has been issued and he is free to return home. Only the elders choose to remain on the planet to die, facing the erupting volcanoes, Timanov retaining his faith even in the face of Amyand's revelation that Logar was merely a man in a fireproof suit: "Another deception!"

The Doctor, meanwhile, succeeds in weakening the Master's hold over Kamelion and interrupts the numismaton experiment. He adds calorific gas to the surge but is unable to prevent the Master from reacquiring his usual size and becoming – he taunts – "a thousand times stronger". As the gas flow alters, the Master is trapped and the Doctor does not intervene despite his oldest enemy's threats and then pleading, watching as he is seemingly immolated. Implored by the terminally wounded Kamelion, the Doctor has put the automaton out of its misery using the TCE. Escaping the destruction of the gas control room in the TARDIS along with Peri, the Doctor lands to pick up Turlough, only to find that he has elected to return to Trion now that he is a free man. Turlough tells Peri to look after the Doctor. He then parts from the Time Lord, thanking him for all that he has learned in his travels with him. As the Doctor and Peri return to the TARDIS, the young American tells him she has a few weeks vacation left and would like to spend it travelling with him. The Doctor accepts and the two embark on new adventures.