The Isos Network (audio story)

 was the fourth and final story of the second series of The Early Adventures, produced by Big Finish Productions. It was written by Nicholas Briggs, narrated by Frazer Hines and Wendy Padbury and featured the Second Doctor, Jamie McCrimmon and Zoe Heriot.

Publisher's summary
The Doctor, Jamie and Zoe are leaving Earth after having successfully defeated a Cyberman invasion... The Cyber-fleet is still exploding... But something is escaping through the mass of vaporising debris.

In hot pursuit, the Doctor and his friends find themselves drawn to a mysterious planet where strange beasts slither through the streets of a deserted city... And an old enemy lurks beneath the streets.

As a force of heavily-armed aliens arrives, a battle to save the entire galaxy from invasion begins.

Part one
The Second Doctor, Jamie and Zoe are leaving Earth in the TARDIS after thwarting the previous Cyberman invasion, when they discover one Cyber-ship escaping and attempt to follow it. However, the TARDIS is damaged in the pursuit and they land on the planet Isos II and decide to go exploring for the ship since the TARDIS needs to re-calibrate. They discover a large seemingly-abandoned city and accidentally step in some slime, then decide to move inside the city and figure out what's going on when they realise no one is around and there's lots of slimy trail. They are surrounded by slug creatures who at first appear to want to hurt them but turn out to be friendly and play with the three. The three are eventually lead to a deserted underground monorail station and Zoe gets trapped in a lift where she is plummeted below.

Meanwhile an Isos ship, named the Braxos, lands on Isos and dispatches a crew to discover the source of an energy spike they picked up and end up finding the TARDIS, the source of the spike. They have been sent to discover what had happened to a colony on Isos II that disappeared. Jamie, while searching for Zoe, ends up falling down a broken escalator while the Doctor is discovered by the dispatched Isos security team. Zoe begins to explore the tunnels but she hears steps behind her and tries to outrun them. The Doctor is brought back to the Isos ship to talk with Commander Seru who demands he explain why the population of the planet they're on, Isos II, has disappeared to which the Doctor doesn't have an answer but a vague suspicion. Jamie stumbles on cyber-pods and the Cybership they were pursuing earlier and realises that the Cybermen have already arrived on the planet. Zoe follows a slime trail, wondering how the slug creatures could have penetrated this deep, only to be cornered by some Cybermen....

to be added

Cast

 * Jamie McCrimmon/The Doctor/Narrator - Frazer Hines
 * Zoe Heriot/Narrator - Wendy Padbury
 * Seru - Rachel Bavidge
 * Enab - Richard James
 * Alam/Hilsee - Kieran Hodgson
 * The Cybermen - Nicholas Briggs

Continuity

 * For the three travellers, this story takes place a few days after the Cyber-invasion of Earth. (TV: The Invasion)
 * Jamie is reminded of the London Underground and the Yeti. (TV: The Web of Fear)
 * Jamie remembers encountering another Cyber-Controller in their tombs on Telos. (TV: The Tomb of the Cybermen)
 * Jamie later recalled facing the Cybermen on Isos when he encountered the Sixth Doctor. (AUDIO: Last of the Cybermen)
 * The Cyber-Controller accesses the repository of cyber-experiences (PROSE: Iceberg) and sees the Doctor as a white-haired old man. (TV: The Tenth Planet) This reference raises additional questions as to the decade that the UNIT stories are set in, as the First Doctor's encounter with the Cybermen takes place in 1986, yet this story takes place only days after the Second Doctor's latest encounter with them. (TV: The Invasion)
 * Jamie asks the Doctor if he will ever learn how to fly the TARDIS properly. He earlier accused him of not being able to control it. (TV: The Tomb of the Cybermen)
 * The Doctor reminds Jamie that the Cybermen have no emotions and wouldn't be able to build a beautiful city. The Cybermen explain to the Doctor on their first encounter that they have rid themselves of emotions. (TV: The Tenth Planet)
 * The Doctor uses the sonic screwdriver again. (TV: Fury from the Deep)
 * Jamie notes the cyber-pods are like the one's in Vaughn's factory. (TV: The Invasion)