Exotron (audio story)

 was the ninety-fifth monthly Doctor Who audio release produced by Big Finish Productions. Released in 2007 it was the the second audio story pairing the Fifth Doctor and Peri Brown. The first, Red Dawn, had been published seven years earlier in 2000. This story is the first of two three-part Fifth Doctor stories (the other being The Mind's Eye), as aside from The Five Doctors all the stories of Peter Davison's run as the Fifth Doctor on television had evenly numbered parts of either two or four episodes.

Publisher's summary
Exotron (A Three-Part Story)

"The Farakosh attack us — and my Exotrons defend us."

On a distant colonial outpost of Earth, a group of terraformers is under threat from the planet's most fearsome predator: the giant carnivorous Farakosh. All that stands between the colonists and a grisly death are the Exotrons — huge robots equipped with devastating firepower, designed by the outpost's leader, Major Taylor.

But all is not as it seems. How are the Exotrons controlled, and where did the colonists find the resources to build them? The Doctor wants answers and Taylor is reluctant to provide them.

Meanwhile, outside the compound, the Farakosh are massing...

Plot
to be added

Cast

 * The Doctor - Peter Davison
 * Peri Brown - Nicola Bryant
 * Hector Taylor - John Duttine
 * Paula Taylor - Isla Blair
 * Sergeant Shreeni / Secretary of the Interior Ballentyne - Nick Brimble
 * Corporal Mozz / Christian - Richard Earl
 * Weiss / Kucha / Computer - Claire Wyatt

The Doctor

 * The Doctor has studied Greek and knows the language.

Individuals

 * Paula is the former wife of Major Hector Taylor.
 * Taylor's co-conspirator in the Exotron project is Secretary of the Interior Ballentyne, whose office is in Brussels, Belgium.
 * Paula had an affair with a lieutenant named Christian, which led to the deterioration of her marriage. He was killed by a Farakosh six months earlier.

Species

 * The Farakosh are a telepathic species. Consequently, the planet is immersed in telepathic fields.
 * Whenever the Exotrons are activated, it causes the Farakosh pain as the Exotron Net disrupts their natural telepathic field.

Government organisations

 * The terraformers answer to the Earth Authority.

Plants

 * Peri studies the xerophytes on the unnamed Earth colony and collects several samples to bring back to the TARDIS.

Continuity

 * Peri uses her botany skills to analyse the plants on the colony. (TV: The Mark of the Rani, Timelash)