Planet of Fire
Planet of Fire was the fifth story in season 21 of Doctor Who. It was the penultimate adventure to regularly feature Peter Davison as the Fifth Doctor.
The story was notable for the departure of Vislor Turlough, the destruction of Kamelion and the introduction of Peri Brown. It was Peter Grimwade’s final script and Fiona Cumming’s last directorial turn for the program. For Turlough’s last story, it was decided that his mysterious past, outlined in TV: Mawdryn Undead, should be explored.
Exteriors were shot on location in Lanzarote in the Canary Islands. The location was chosen after Cumming promoted it with photos from her holiday. Grimwade decided to use the island for multiple settings and the island’s volcanic landscape also doubled for the planet Sarn. Grimwade had trouble writing for the setting, having never been there. John Nathan-Turner denied his request to accompany the select members of the crew to the island.
On the desolate volcanic planet Sarn, chief elder Timanov counsels the young Chosen One Malkon on how to act in the wake of increased seismic activity, heralding the imminent volcanic catastrophe known as the Time of Fire. Their god Logar, the devout Timanov warns, is greatly displeased at the number of unbelievers. As the Chosen One – so chosen due to the triangular “Mark of Logar” on his arm – Malkon has sole authority to assign heretics to burn in the Cave of Fire and thereby appease their god. Malkon doubts his resolve to condemn unbelievers to death. Meanwhile two such unbelievers, Amyand and Roskal, scale the forbidden Mountain of Fire – believed to be Logar’s dwelling place – and find the crater at the top empty. Now fully convinced that Logar is a myth, they return to the village to spread the news.
As the Fifth Doctor muses bitterly about Daleks and the departure of Tegan, Kamelion’s agonized cries are heard from an adjoining room. He has linked himself to the TARDIS data core. The TARDIS then picks up a distress signal; Turlough recognizes the pattern and is sufficiently dismayed that he disables the communicator to stop the signal. The TARDIS coordinates have been changed, apparently by Kamelion, and they are en route to the source of the signal, the island of Lanzarote.
American archaeologist Howard Foster and his team are trolling the nearby seabed for ancient relics. Among the artifacts they pull up is a strange, anachronistic metal object also bearing the Mark of Logar. Howard’s restless stepdaughter Peri Brown, accompanying the expedition while on holiday from university, is bored and wants to travel with her friends to Morocco. Howard appears to relent, but strands her on the boat to make her miss her flight. Peri is furious at Howard, but finds his wallet full of money and an alien object Howard had fished out of the lake. She thinks it may be worth some money. Peri strips to her bikini and stuffs the artifact, Howard’s money and her clothes into a plastic bag. She then jumps in the sea and begins swimming to shore.
While the Doctor explores the island trying to find the source of the signal, Turlough has returned to the TARDIS, where he finds Kamelion at the console trying to establish contact with an unknown entity. Turlough overloads the console to disable him out of anger, thinking the signal may be from Trion. On the monitor, he sees Peri struggling in the water and beginning to drown. He pulls her ashore and takes her to Tegan’s old room to recuperate. He finds the alien artifact in the bag, pulling up his sleeve to show that he too bears the Mark of Logar on his arm. While Peri tosses and turns, muttering incoherent apologies, Kamelion seizes on her psychic impulses and transforms into Howard. The Doctor has traced the signal back to the artifact now in the TARDIS. The doors close and the TARDIS takes off automatically, apparently returning the object to its planet of origin, Sarn. Kamelion enters as Howard, but his mannerisms are like someone else’s. After putting her clothes back on over her swimsuit, Peri enters the control room, confused as to where she is.
In the great hall on Sarn, Timanov and Malkon attempt to quell the citizens’ unrest due to the impending Time of Fire. The arrival of Amyand and Roskal with the news of their findings causes even more disruption. A desperate Timanov calls for a sign from Logar, and a burst of flame from the Cave of Fire is the apparent answer. Timanov seizes this as a call from Logar to burn the unbelievers. Just then, a lookout announces the arrival of the TARDIS, describing it in a way that corresponds with their legend of the Outsider, a representative of Logar. Timanov urges Malkon to condemn the heretics, but he hesitates.
Once the Doctor and Turlough leave to explore, “Howard” announces that contact has been established, and that he now has control of the TARDIS. As he laughs maniacally, his features change into that of the Master before Peri’s horrified eyes.
The Doctor and Turlough explore the apparently deserted village square finding the triangular pattern, which Turlough identifies as the Misos Triangle, etched on a column. The Misos Triangle is an emblem of Turlough’s home planet, Trion, but he is not forthcoming with further details. They do not notice another TARDIS materializing nearby.
The Master’s control of Kamelion is tenuous, and the shape-shifting robot momentarily regains self-control. He removes the TARDIS’s comparator and urges Peri to give it to the Doctor, but then loses his self-will and his form shifts back to the Master. He pulls her out into the village square towards the Master’s TARDIS, but a sudden tremor knocks it over, door-side down, and allows Peri to escape into the desolate wilderness. The Master, trapped inside his TARDIS, orders Kamelion to pilot the Doctor’s TARDIS inside his own, but without the comparator it won’t function.
The unbelievers storm the great hall, having found and befriended the Doctor and Turlough, displaying the travelers as the Outsiders. Turlough discovers the Misos Triangle on Malkon’s arm, showing his own. He is convinced that the relics in the hall are from his father’s ship, and that Malkon might be his younger brother. Malkon describes how he was found in the Place of Fire as an infant, and Turlough convinces him to take him there, where they find the wreckage of a crashed spaceship. They encounter Peri, who had been wandering lost since eluding the “Master”. When Turlough learns that the Master is involved, they dash back to the village to warn the Doctor.
The Doctor, however, finds himself at the mercy of Timanov and his own Outsider, the Kamelion/Master. Under the “Master’s” sway, Timanov orders the sacrifice of the unbelievers to the flame. The “Master” demands the return of the comparator, which of course the Doctor doesn’t have, as his new allies are pushed toward the mouth of the Cave of Fire.
Malkon demands that the execution cease, but is shot down in the ensuing struggle. Turlough uses a Trion relic to remotely disable the sacrificial flame, which Timanov shows as a sign of displeasure from Logar at Malkon’s apparent assassination. Still fooled by the “Master”, Timanov leads a team of Sarns in helping to shift the Master’s TARDIS, but once upright, the “Master” pulls Peri inside and de-materializes.
The Doctor struggles to figure out why the Master is on Sarn, and how to rescue the citizens from the impending doom of the volcanic eruption. He also reasons that the Trions had a more productive use for the Cave of Fire than mere sacrifice. Timanov speaks of a time when he was young, and he encountered Logar who took him to a bath of blue flame that rejuvenated him.
The Master’s TARDIS materializes in a control room deep below the volcano. The “Master” enlists Peri’s assistance, on pain of death from his Tissue Compression Eliminator weapon, in controlling the machinery there to harness the power of Numismaton Gas, which is indeed a bright blue flame renowned for its healing properties. The Doctor takes advantage of the presence of the Numismaton flame to heal the ailing Malkon in the Cave of Fire. Eluding the Kamelion/Master and ducking into the Master’s TARDIS, Peri locates what she reasons must be Kamelion’s control box. Lifting the lid, she finds the Master lurking within, reduced to mere inches in height.
The Master, having accidentally shrunk himself while attempting to upgrade his TCE weapon, seeks the power of the Numismaton Gas to restore himself. He constructed the control box to re-establish contact with his slave Kamelion to help him reach Sarn.
The Doctor and Amyand, with Peri’s help, have reached the Numismaton gas control room. They find protective metallic suits which correspond with the traditional image of Logar. The Doctor realises that the Trions have used the control room to regulate the seismic activity, but the impending eruption will be too big to control. Kamelion pilots the Master’s TARDIS into the blue flame and brings out the control box, bearing the Master within. As Kamelion advances menacingly on the Doctor with the TCE, he overloads the gas control circuitry to give Kamelion a near-fatal “heart attack”. Kamelion, now freed from the Master’s control, begs for destruction, and the Doctor complies with the TCE.
The Master is restored to full height by the Numismaton gas, and gleefully describes the tortures that await the Doctor at his hands. But the Doctor’s fiddling with the controls cuts off the gas, leaving the Master to burn in the full power of the naked flames. The Master’s pleas for mercy go unheeded, and the Doctor watches as his enemy is apparently consumed by fire.
Turlough, despite his status as a Trion political prisoner, swallows his pride and manages to re-activate the communication system in the wreckage of his father’s ship, summoning a Trion rescue ship to pick up the Sarn survivors. Timanov, humbled by his easy manipulation by the Master in the name of his god, declines rescue and opts to perish in the ensuing volcano. Acting on instructions from the Doctor, Turlough programs the TARDIS to rescue the Doctor and Peri from the gas control room before it is destroyed. The Trion captain Lomand informs Turlough that due to general amnesty, his exile has been lifted and he is free to return home. Turlough thanks the Doctor, who understands Turlough’s reasons for wanting to return to Trion, for everything and the two warmly bid each other farewell. Peri, on the other hand, asks to travel with the Doctor for the remaining three months of her vacation. The Doctor agrees, and he welcomes her aboard the TARDIS as it takes flight.