The Enemy Beyond (audio story)

The Enemy Beyond was the first story in the audio anthology Between Two Worlds, produced by Big Finish Productions. It was written by Andrew Smith and featured Jemma Redgrave as Kate Stewart, Ingrid Oliver as Petronella Osgood, James Joyce as Josh Carter, Tracy Wiles as Jacqui McGee and Mark Bonnar as the Eleven.

Publisher's summary
In a UNIT facility beneath Edinburgh Castle, Kate and Osgood work to unlock the mystery of a stone arch discovered buried in a prehistoric rock formation.

When the arch takes one of their number away to a strange, bleak world, it leads to an encounter with a Time Lord. One with multiple personalities. Soon the Eleven is loose on the streets of Edinburgh and plotting to seize the arch from UNIT by any means necessary.

Plot
Jacqui interviews Professor Adam Merchant in a submarine off of the west coast of Scotland regarding his team's mission to map the seabed and drill for minerals. Maria cracks a sixty-million-year-old rock, which explodes and reveals a glowing stone arch inside, covered in symbols. Jacqui decides to put Merchant in touch with Kate.

UNIT has the Arch secured and taken to a scientific base under Edinburgh Castle where Kate introduces Merchant to Osgood, who is analysing the artefact and confirms that it is likely of extraterrestrial origins. Osgood finds circuitry inside the stone and Merchant offers to contact palaeographers to attempt to decode the symbols; when he touches one of the symbols, there is a bright light and he disappears. Osgood analyses the event and finds new soil on the ground, brought in by the Arch and indicating that Merchant has been teleported.

Merchant finds himself blinded in a new world and meets the Eleven. The Eleven explains that there is another arch here, but that the portal can only be opened from the Earth side and that he himself came through another one long ago. He claims that he lost his memory and that his other incarnations, living within his mind and speaking through his mouth, are other people that he arrived with. Merchant shares his story and wears a bandage over his eyes for two days at the Eleven's suggestion to allow him to heal.

Kate sends Josh and his team through the Arch in survival suits to recover Merchant, who removes his bandage as the Arch lights up and realises that the Eleven is the only one with him. The two of them are brought to Earth and find that only hours have passed there since Merchant disappeared. Kate has the Eleven taken to her office and kept under guard whilst she and Osgood speak with Merchant about his experiences on the other side of the Arch. The Eleven kills Private Roberts and heads back to the laboratory, but is forced to escape when the doors are sealed.

Josh shows Kate and Osgood CCTV of the Eleven escaping onto the streets of Edinburgh and is charged with coming up a contingency plan to get the Arch to London. Whilst Merchant slips away from the base and tells Jacqui what has happened to him, the Eleven hypnotises a police officer into serving him without question. Jacqui calls Kate when Merchant's hands start being covered in webs, but he leaves out of the bathroom window before Kate and Osgood arrive and kills a taxi driver. The Eleven learns of this from the police officer, follows Merchant to Arthur's Seat and convinces him to infiltrate UNIT after giving him a temporary cure.

Kate, Osgood and Josh look at the body of the taxi driver, covered in webs. Kate locates the Eleven and Merchant, but the police officer grabs her and the Eleven knocks her out and takes her captive, demanding access to the Arch and admitting that he put a toxin in Merchant's food. He had hoped that the toxin would activate upon passing through the Arch and being exposed to Earth's carbon dioxide, killing Merchant and everyone around him, but the sterile environment of the laboratory prevented this.

Three hours after Kate's disappearance, Osgood and Josh invoke the Lionheart Protocol and have the Arch moved to Edinburgh Airport to be flown to London. The Eleven follows the convoy and has Merchant kill the police officer, leading Kate to tell Osgood and her colleagues to leave. Kate, the Eleven and Merchant board the aeroplane where Josh and his soldiers lie in wait and arrest the Eleven. He manages to use Kate as a hostage long enough to grab a parachute, intending to leave the UNIT members to be infected by Merchant. However, Merchant grabs the Eleven and jumps from the plane with him.

Merchant's body is recovered from the ocean but the Eleven's is not, so Kate decides to assume that he is alive and keep the Arch protected. Osgood has had difficulty examining the toxin and antitoxin and requires the help of Harry Sullivan, currently in Australia to give a talk on UFO sightings. Harry calls Kate back and invites her and Osgood to join him and UNIT Australia in investigating a spacecraft in the desert containing Ice Warriors.

Cast

 * Kate Stewart - Jemma Redgrave
 * Osgood - Ingrid Oliver
 * Josh Carter - James Joyce
 * The Eleven - Mark Bonnar
 * Adam Merchant / Police Officer - James MacCallum
 * Jacqui McGee - Tracy Wiles

Worldbuilding

 * Merchant is a marine geologist and archaeologist. He started out in archaeology, mainly in the Mediterranean and Aegean, and once found a three-thousand-year-old Egyptian shipwreck beneath the former.
 * Maria pilots the drilling submarine.
 * Jacqui stays with her parents.
 * Jacqui and Merchant attended Heriot-Watt together.
 * Sixty-million years ago was the Palaeogene Era. Osgood believes that this is far too late for the Silurians.
 * The Eleven gives Merchant broth.
 * The Six makes Merchant nervous.
 * Private Roberts guards the Eleven outside Kate's office. The Eleven kills him.
 * Merchant kills a taxi driver on Dalkeith Road.
 * Kate tells the Eleven about the Lionheart Protocol.
 * The arch is loaded onto a Hercules transporter at Edinburgh Airport.
 * Josh mentions Sam Bishop.

Continuity

 * Josh speculates that the web substance could be caused by the Yetis again. (TV: The Web of Fear et al)
 * Kate mentions her dealings with, (AUDIO: Master of Worlds) (TV: Death in Heaven) and the Doctor. (TV: The Power of Three, The Day of the Doctor, Dark Water / Death in Heaven, The Zygon Invasion / The Zygon Inversion)
 * Josh calls Harry an "international troubleshooter", a descriptor also used for Sam Bishop. Osgood says that he will be jealous. (AUDIO: Vanguard)