'Planet of Fire' (4 Parts) Story Code '6Q' by Peter Grimwade

On Lanzarote on Earth, archaeologist Howard Brown has raised a hoard of ancient artefacts from the seabed, amongst which is an alien signalling device. Aboard the TARDIS, the android Kamelion is behaving oddly; it receives a signal and pilots the space / time craft to Lanzarote. When the Doctor and Turlough investigate the signal, Turlough rescues Howard's stepdaughter, Peri, from drowning, only to find that the alien device that she has taken carries the same mark that is on his arm. Kamelion becomes possessed by Peri's subconscious mind, assumes the appearance of Howard, and takes the TARDIS to the planet of Sarn, where the planet's people are split into two factions: those who worship the volcano god Logar, and are led by the High Priest, Timanov, and Malkon, the 'Chosen One'; and the Unbelievers, led by Amyand and Sorasta. The Doctor and Turlough are brought by the Sarns to their underground control centre, where Turlough recognises some of the equipment as belonging to his father's ship. Meanwhile, the Master has possessed Kamelion; appearing before Timanov, it is mistaken by him for Logar. The Kamelion-Master orders Timanov to have the Doctor burnt to death, but Turlough saves the Time Lord by redirecting the flame. When Kamelion encounters Peri, it struggles between her control and the Master's. Peri discovers that the Master has been miniaturised in an accident caused when the renegade Time Lord was experimenting on his Tissue Compression Eliminator; the Master has travelled to Sarn to use the restorative powers found in the volcano's blue flame, caused by the ignition of the naturally occurring numismaton gas, to regain his size and extend his life. Turlough reveals that he is from the planet Trion; his family were branded as political prisoners - he was sent in exile to a public school on Earth, while his father and brother were sent to Trion, a prison planet. Turlough's father was killed in the crash, but his brother, Malkon survived. As the volcano threatens to destroy Sarn, Turlough uses the crashed ship's radio to contact Trion, only to find that his exile has been rescinded. Kamelion carries the Master into the blue numismaton flame, and then begs the Doctor to kill it, rather then be the Master's slave. As the Doctor and Peri look on, the flame restores the Master's size, but then turns orange, burning him to death. A spaceship from Trion arrives to evacuate the doomed planet's inhabitants; Turlough elects to return to his home world, while Peri joins the Doctor in the TARDIS.

Peter Davison (The Doctor), Mark Strickson (Turlough), Nicola Bryant (Peri), Peter Wyngarde (Timanov), Anthony Ainley (The Master), Barbara Shelley (Sorasta), James Bate (Amyand), Dallas Adams (Professor Howard Foster), Gerald Flood (Voice of Kamelion), Edward Highmore (Malkon), Jonathon Caplan (Roskal), Michael Bangerter (Curt), Simon Sutton (Lookout), Max Arthur (Zuko), John Alkin (Lomand)

Produced by John Nathan-Turner
Directed by Fiona Cumming

TX:
Part 1 - 23rd February, 1984 @ 6.40pm - 7.05pm
Part 2 - 24th February, 1984 @ 6.40pm - 7.05pm
Part 3 - 1st March, 1984 @ 6.40pm - 7.05pm
Part 4 - 2nd March, 1984 @ 6.40pm - 7.05pm

Notes:
*Featuring the Fifth Doctor, Turlough and Kamelion, and introducing Perpugilliam 'Peri' Brown

*Working title: 'Planet of Fear'