The Jupiter Conjunction was the one hundred and sixtieth story in Big Finish's monthly range. It was written by Eddie Robson and featured Peter Davison as the Fifth Doctor, Sarah Sutton as Nyssa, Janet Fielding as Tegan Jovanka and Mark Strickson as Turlough.
Eight slash Q Panenka, a craggy comet with a 13km circumference, has an elliptical orbit that takes it between Earth and Jupiter. Which, in the year 2329, makes it a cheap means of space freight — the second class postal service of the solar system.
But when the TARDIS lands on Panenka, the Doctor, Tegan, Turlough and Nyssa discover a community falling apart at the seams — plagued by thefts, and mysterious disappearances among the "piggybackers" who eke out a desperate existence on the comet.
While Tegan and Nyssa suit up for a dangerous excursion into the comet's Unstable Zone, the Doctor and Turlough find themselves pawns in a game that could lead to tragedy for both Earth and Jupiter alike...
The TARDIS materialises on the comet Eight slash Q Panenka in 2329. It is equipped with a shopping centre for the benefit of the freight service's employees, which includes a Mexican restaurant and numerous clothing shops. While browsing in one such shop, Nyssa meets a young woman named Violet Silvaner who describes herself as a "piggybacker". Violet has stolen a space suit as the Panenka Haulage Company, which runs the freight service on the comet, refuses to sell her one as she was not supposed to have been on Eight slash Q Paneka in the first place. She tells Nyssa that her friend Manny disappeared while on the surface of the comet.
The Doctor tells Turlough that the man who discovered Eight slash Q Panenka was "an old friend" shortly before the two of them are arrested by Anton Falcao, the Head of Responsibility on the comet, as the TARDIS' materialisation was witnessed on the security cameras. He believes that they are responsible for the theft of 11.3 cubits of material over the course of the last several months. Turlough tells him that Nyssa and Tegan are hitch-hikers that they had only recently picked up and that he did not even catch their names. As Falcao cannot offer the Doctor and Turlough legal representation since they are not residents of the comet, they will be forced to represent themselves in their trial which is to begin at 1900 hours later that day.
Having been provided with the security camera footage of the theft of the materials from the comet's hold, the Doctor decodes it only to discover that it shows the TARDIS materialising inside the hold and the relevant materials disappearing when the TARDIS dematerialises. Although Turlough suggests that his future self may have travelled to Panenka at a later point in his personal timeline, the Doctor dismisses this as a possibility and instead believes that they are being framed. After this revelation, Turlough asks to see Falcao and "confesses" his role in the theft on the condition that he is given immunity from prosecution. He tells Falcao that he is willing to testify against the Doctor at his trial.
Having been discovered on the surface of the comet by Nyssa, Tegan and Violet, Manny claims that he was struck by a lightning bolt generated by creatures made from clouds. However, Nyssa believes that his spacesuit may have shorted out and electrocuted him and his claims to have seen such creatures are the product of delirium. Nyssa attempts to use Violet's neural disruptor as a makeshift defibrillator but her efforts are unsuccessful and Manny dies. From Violet's reaction, Tegan realises that Manny was her boyfriend.
The Doctor's trial, which is presided over by Patricia Walton, is held in the centre of the Panenka plaza as the comet does not have a courtroom. The Doctor gives his name as "Dr. John Smith". Walton is empowered to determine the Doctor's guilt or innocence and pass sentence on him by virtue of the Constitution of Panenka. In his testimony against the Doctor, Turlough claims that the two of them stole the materials from the hold in order to sell them on and make a fortune. He tells the court that the TARDIS is incapable of carrying cargo over great distances and that the materials are hidden at various locations around the comet. Having been presented with a map, Turlough picks out several places at random, one of which is the Unstable Zone which was rendered uninhabitable by an accident in 2323. Although Walton believes that his evidence lacks credibility, Turlough claims that he and the Doctor must have gotten lucky. Falcao and two of his men go to investigate.
After being returned to the break room, Turlough reveals to the Doctor that he was merely pretending to betray the Doctor and that his plan was to ensure that the vast majority of the security guards were outside the settlement investigating the alleged locations of the materials so that it would be easier for the two of them to escape.
While it is attempting to land in the Unstable Zone, Falcao's shuttle is struck by lightning and crashes on the surface of the comet. He is the only survivor.
After being confronted by Falcao's deputy Chica St. Jude during their attempt to escape, the Doctor and Turlough determine that the materials were stolen by Walton and her adverse reaction to the prospect of Falcao investigating the Unstable Zone suggests that there is something there which she seeks to keep hidden. As Walton would not allow her to investigate, Chica helps the Doctor and Turlough reach the TARDIS. In order to ensure that Walton does not learn of her betrayal, Turlough pretends to take Chica as a hostage and threatens to kill her.
While Tegan and Violet are investigating the existence of a previously unknown complex on the other side of the comet, the cloud creatures invade the shuttle, kill Falcao and take Nyssa prisoner. While Tegan manages to escape, Violet is likewise taken prisoner and brought to their complex.
The cloud creatures are known as the Jovians, a species native to the atmosphere of Jupiter who are unknown to the vast majority of humanity. They are in the employ of Major Nash of the Jupiter Axis Military. Nash is overseeing the construction of a long-range particle cannon using the materials stolen from the Panenka cargo hold.
The Doctor had previously believed that the Jovians had become extinct prior to the emergence of human civilisation, let alone the colonisation of Jupiter. He tells Tegan and Turlough that the Jovians once had a beautiful civilisation which they had created entirely in their minds. He describes the process as being similar to whale song.
Nash tells Nyssa that Earth and Jupiter are at war as the former seemingly objects to the less regimented nature of the latter's society. Violet reveals that she is in fact a lieutenant colonel in the Jupiter Axis Military who was working undercover on the comet.
Using the images which Tegan took of the complex as evidence, Chica reveals via the intercom that Walton conspired with the Jupiter Axis Military to create the long-range particle cannon. Walton claims that the plan was to use the cannon to shift the orbit of the comet to ensure that it would remain in conjunction with Jupiter for the next fifteen years. Walton is killed by Violet shortly after her arrival at the complex.
As Panenka is an Earth protectorate, Violet considers its inhabitants to be the enemy and orders the Jovians to attack the settlement and leave no survivors.
The Jovians' plan is to use the long-range particle cannon to turn Jupiter into a second sun and colonise Earth. However, according to a news broadcast, Earth and the Jupiter Axis have reached a peace agreement. The Doctor determines that Violet manipulated Tegan into revealing the presence of the Jovians on the comet and the Jovians themselves into the attacking the settlement in order to prevent the existence of the particle cannon being revealed to Earth. She had hoped that this would result in the creation of a stronger military alliance between Earth and the Axis as they would be united against a common foe, namely the Jovians. Nash, who had spent the previous four years overseeing the construction of the cannon, was as ignorant of the peace agreement as the Jovians. Consequently, Violet resorts to Plan B, which is to present Nash as a rogue officer who plotted to destroy Earth behind the Jovians' backs. Given that Violet has disabled his gun, Nash kills her with his bare hands. Leaving Nyssa handcuffed to his desk, he activates the cannon and points it at Earth. It is on a countdown of 26 minutes.
In order to prevent the attack on Earth coming to fruition, Tegan suggests altering the course of the comet by destroying a section of it. A by-product of this explosion will be to send Panenka into the path of the cannon's blast. In order to ensure that nothing interferes with this plan, the Jovians remain in the settlement and amplify the explosion using their telepathic abilities. Their efforts are successful and the blast dissipates into space. The comet is sent hurtling into space.
After Nash deactivates the process which stabilises the Unstable Zone, one of the Jovians rescues Nyssa and brings her to the TARDIS, which Violet had ordered him to place in the TARDIS. Nash is killed following the disintegration of the control room. The Hostile Action Displacement System activates and the TARDIS materialises on the shuttle.
The Jovians which saved Nyssa plans to travel to Earth and reveal the existence of his species to humanity. Chica tells the Doctor that the former inhabitants of Panenka will not inform the Earth authorities about the Jovians' attack on their settlement as doing so would result in the outbreak of war.
- The Doctor - Peter Davison
- Nyssa - Sarah Sutton
- Tegan - Janet Fielding
- Turlough - Mark Strickson
- Patricia Walton - Rebecca Front
- Anton Falcao - John Cummins
- Chica St Jude - Ellie Burrow
- Violet Silvaner - Zoe Lister
- Major Nash - Ben Porter
- Manny - Simon Blake
- The Jovians - Philip Pope
- Nyssa has spent the morning reading in the TARDIS library.
- Eight slash Q Panenka, which is 13 kilometres in diameter, orbits the Sol system every three years and three months. The Doctor determines that the comet is approaching conjunction with Jupiter.
- Sam Chung is the President of Eurasia.
- The Doctor refers to Nyssa's recent rejuvenation in India on 31 December 1926 (AUDIO: The Emerald Tiger), and his regeneration into his fourth incarnation. (TV: Planet of the Spiders, Robot)
- The Doctor and Nyssa both recall his failure to save Adric's life. (TV: Earthshock)
- The Doctor and Turlough wear atmospheric suits from the TARDIS. (TV: Four to Doomsday)
- The Doctor refers to the TARDIS' Hostile Action Displacement System. (TV: The Krotons)
- As she believes that she will die in the destruction of the Unstable Zone, Nyssa reflects that she has so much more to do, namely cure Richter's Syndrome. (AUDIO: Cobwebs)
- While she and the Doctor are operating under the misapprehension that Nyssa is dead, Tegan prepares to tell the Doctor about Nyssa's husband Lasarti and their children Neeka and Adric Traken. (AUDIO: Winter, Heroes of Sontar, Prisoners of Fate)