The Auton Infinity (audio story)

, also marketed as Forty: Volume 2, was an audio story written by Tim Foley and featured Peter Davison as the Fifth Doctor, Janet Fielding as Tegan Jovanka, Mark Strickson as Turlough and Jon Culshaw as Kamelion, Brigadier Lethbridge-Stewart and. It also concluded the Fifth Doctor's "jumping time tracks" narrative.

Publisher's summary
Snowdonia. UNIT is running a training exercise with the Brigadier in attendance. Except it isn’t long before things start to go badly wrong. The fake aliens primed to attack the troops might not be so fake after all, and a temporal disturbance attracts the Doctor, Tegan and Turlough into the fray.

Old enemies are on the scene with a deadly plan - but they might be the least of the Doctor's worries.

Because he's recently been sent backwards and forwards through his own lifetime...and he’s finally going to find out why.

Part one
The Doctor, Tegan and Turlough are buffeted around the TARDIS control room for hours after leaving Frontios and eventually materialise in Snowdonia. They wander into a UNIT training exercise and are taken by Sergeant Wharry to the retired Brigadier Lethbridge-Stewart, who explains that the exercise involves an invasion during a peace conference. The soldiers tasked with roleplaying as aliens deviate from the route, however, and the Doctor's diversiform intensifiser detects temporal energy.

Borrowing Wharry's car, the Doctor, Turlough and Captain Mears go to investigate whilst Tegan remains behind with the Brigadier to keep an eye on things, but a jamming signal is emitted from the opposite direction and Mears decides that it needs to be dealt with first to ensure that UNIT are able to communicate. A plastic alien mask latches onto Mears' face and the Doctor zaps it off with his intensifiser, deducing that the Nestene Consciousness is responsible and going to warn the Brigadier. He notices a circus tent and enters with Turlough and Mears, after which they are greeted by gas and a hologram of.

Part two
The gas is a harmless gas from Tersurus and the Doctor uses the Master's console to stop the broadcast of the signal, which actually originates from a distant source. He informs the Brigadier and Veronica Holmes from the Ministry of Defence of the threat of the Nestenes and the Master and learns that Tegan and Wharry have left, confronting the Auton Prodigal and the soldiers being controlled by the masks. After taking the two humans to an abandoned manor, Prodigal shoots Turlough and captures the TARDIS, which she intends to destroy to build a bridge for the Master in return for a keystone.

The Doctor sends out a pulse which severs the link between the soldiers and their masks, sending the masks scuttling away. Corporal Palmer sees to the wounded, but Dodson dies despite Mears having ordered non-lethal force. The Doctor, the Brigadier, Mears and Veronica find that Prodigal has replaced the TARDIS interior with raw vortex energy through which she has sent Tegan and Turlough. She tells them that the Master is behind a sort of mask and, after the Brigadier shoots Mears due to his first initial paired with his surname is an anagram of "Master", the Doctor realises that the Brigadier is actually the Master. He unmasks himself.

Part three
The temporally dislocated Doctor wakes up on a stone spaceship with the Brigadier, who explains that he was kidnapped on his way to a UNIT exercise in Snowdonia, and escapes by picking the lock. He breaks out Tegan and Turlough, who tell him and the Brigadier about Snowdonia, and informs his three companions of his dislocation before they split up. Turlough and the Brigadier spy on the Master and Prodigal and, when they leave, they access a map which points them to the keystone, which resembles a coffin.

The Doctor and Tegan find an altar to a pool of molten plastic which rises and forms a wall, attempting to communicate with them through stick figures and telepathy. The plastic explains how an Old One decayed and hid in a fold in time before it was scattered across space, some of its pieces finding one another and becoming Nestenes. Some parts mourned for their original form, however, and Tegan deduces that Prodigal is one such part. The Doctor feels the Nestene in his mind and realises that he is not really the Doctor; he has been leaping around his timeline to enter the body of an Auton and be part of the Consciousness.

Part four
Turlough and the Brigadier find the real Doctor in the keystone and disconnect him, stopping the ship, which the Auton Doctor realises is a vortex driller. The Master stole the ship and saved Prodigal from the Valley of the Lost near the Death Zone where she had been Time Scooped, a process which had severed her link with the Consciousness and which meant that she now wishes to form a new collective. She has been promised the Doctor, whose mind will be able to lead her to the first Consciousness.

The Doctor wakes up with Turlough and the Brigadier and goes with them to the crux where all of the bridges meet, chased by the plastic masks. He identifies the bridge to take them back to Snowdonia, but the Master places the Auton Doctor into the keystone and they run before the drilling commences. As the Auton Doctor has a plastic brain rather than that of a Time Lord, it is unstable and Prodigal has Tegan help her try to steady the ship. The Auton Doctor realises that the primitive technology is pulling on his timeline and is causing him to slip through time once more.

Part five
The Auton Doctor finds himself as a psychic projection in the TARDIS with Kamelion, who tells him that the interior has been disconnected from the exterior by the snapping of the bridge between Snowdonia and the driller, which has left the exterior as an empty police box. The driller is now being dragged towards the source of the mysterious signal, which Kamelion decrypts and finds is a Nestene signal in the rings of Saturn in the 36th century.

The Doctor, Turlough and the Brigadier, having arrived in Snowdonia, are joined by Veronica and Wharry and drive to the Master's TARDIS. There, the Doctor traces the origins of the mysterious signal and materialises aboard the driller when it emerges from the Time Vortex thanks to Tegan, the Master and Prodigal, the latter of whom is losing her form due to her being completely cut off from her Autons. The first Consciousness has latched onto the ship and is making a psychic connection with it, an action which the Doctor believes will remain in the Nestenes' race memory and which will allow it to become all-powerful.

Part six
to be added

Cast

 * The Doctor - Peter Davison
 * Tegan - Janet Fielding
 * Turlough - Mark Strickson
 * The Brigadier / The Master / Kamelion - Jon Culshaw
 * Prodigal - Juliet Aubrey
 * Veronica Holmes - Lucy Fleming
 * Sergeant Wharry - Fiona Hampton
 * Captain Mears - Oscar Pearce
 * Corporal Palmer - Homer Todiwala
 * Dodson / Autons - Glen McCready

Uncredited cast

 * Peri Brown - Nicola Bryant

Crew

 * Cover Art - Ryan Aplin
 * Director - Ken Bentley
 * Executive Producers - Nicholas Briggs and Jason Haigh-Ellery
 * Music - Howard Carter
 * Producer - David Richardson
 * Script Editor - John Dorney
 * Sound Design - Lee Adams
 * Writer - Tim Foley
 * Brigadier Lethbridge-Stewart © Hamish & Lincoln, with thanks to Hannah Haisman and Candy Jar
 * Autons created by Robert Holmes

Continuity

 * The Brigadier is still officially retired from UNIT. (TV: Mawdryn Undead, The Five Doctors, Battlefield)
 * The TARDIS is still being drawn to the middle of the universe. (TV: Frontios)
 * "The Brigadier" refers to Charles Crichton. (TV: The Five Doctors)
 * The Doctor refers to the Gravis. (TV: Frontios)
 * Tegan believes the Doctor is still missing the Sonic Screwdriver. (TV: The Visitation)
 * UNIT had previously served as security for peace conferences in TV: The Mind of Evil and Day of the Daleks.
 * Turlough is embarrassed about the idea of driving in the Brigadier's presence, with the Brigadier still upset with him for crashing his own car. (TV: Mawdryn Undead)
 * The Doctor reminds Turlough that the Brigadier taught him at Brendon Public School. (TV: Mawdryn Undead)
 * Captain Mears refers to London being invaded by the Yeti, (TV: The Web of Fear) dinosaurs (TV: Invasion of the Dinsaurs) and the Loch Ness Monster. (TV: Terror of the Zygons)
 * The Master previously formed an alliance with the Autons and he disguises his TARDIS as a circus tent, which the Doctor picks up as a hint. (TV: Terror of the Autons) He reacquainted with them in the Death Zone on Gallifrey. (TV: The Five Doctors)
 * The Doctor wonders if the military is being run by Rowlands (TV: Terror of the Autons) and Horatio Chinn. (TV: The Claws of Axos)
 * The Master doubts he would become a woman. Later in his timeline, he would regenerate into his Missy incarnation. (TV: Deep Breath, et al)
 * The earlier Doctor has just encountered the Cybermen on Telos (AUDIO: Secrets of Telos) and the Ice Warriors. (AUDIO: God of War)
 * Tegan recalls the Tomb of Rassilon. (TV: The Five Doctors)
 * The Brigadier's memories of the Tomb of Rassilon are vague. Turlough theorises that the Time Scoop bringing the Doctor's companions out of their timeline had affected their memories. (TV: The Five Doctors, School Reunion)
 * Turlough tells the Brigadier about his alliance with the Black Guardian. (TV: Mawdryn Undead to Enlightenment; AUDIO: Gardens of the Dead)
 * The earlier Doctor remembers Tegan and Nyssa telling him about Adric's death, an event in his personal future. (TV: Earthshock, AUDIO: Secrets of Telos)
 * Tegan recalls the Doctor feeling the effects of his past incarnations being taken out of time by the Time Scoop. (TV: The Five Doctors)
 * The Brigadier was unaware that Turlough was from another planet. (TV: Mawdryn Undead, Planet of Fire)
 * The Brigadier remembers capturing the Master once (TV: The Dæmons) before he escaped. (TV: The Time Monster)
 * Whilst reading Tegan's mind, Prodigal sees the day she met the Doctor on the day her aunt Vanessa died (TV: Logopolis) and encountering the Cybermen (TV: Earthshock, The Five Doctors; AUDIO: Secrets of Telos, Conversion)
 * The Master refers to the Martian Pyramids. (TV: Pyramids of Mars)
 * The Doctor hopes the Brigadier doesn't end up on Nerva Beacon. (TV: The Ark in Space, Revenge of the Cybermen)
 * The future Doctor still has possession of the Seal of Rassilon, which his third incarnation took from the Master in the Death Zone. (TV: The Five Doctors)
 * The TARDIS previously became an empty shell in TV: The Wheel in Space and will do so again in(TV: Father's Day.
 * The Doctor refers to the Brigadier as "the original, you might say." (TV: The Five Doctors, The Doctor Falls, Twice Upon a Time)
 * The Doctor refers to the Arc of Infinity. (TV: Arc of Infinity)
 * Tegan recalls Nyssa collapsing after leaving the Urbankan ship. (TV: Four to Doomsday)