Trail of the White Worm (audio story)

Trail of the White Worm was the fifth story in the first series of the Fourth Doctor Adventures, produced by Big Finish Productions. It was written by Alan Barnes and featured Tom Baker as the Fourth Doctor and Louise Jameson as Leela.

It offered an explanation as to why looked different between the version played by Peter Pratt and the one played by Geoffrey Beevers, revealing that the Master managed to partially reverse his deformity after absorbing some energy from the Eye of Harmony, transitioning him from a more skeletal appearance to a slightly rejuvenated appearance in comparison.

Synopsis
The legend dates back to Roman times, at least: a great White Worm, as wide as a man, slithers out of the rocks of the Dark Peak Gap to take animals, sometimes even children, for its food.

When the Doctor and Leela arrive in the wilds of Derbyshire, only to get caught up in the hunt for a missing girl, they soon discover that the legend of the Worm is very much alive — even now, in 1979.

Worse still, it seems that the Doctor isn't the only renegade Time Lord on the trail of this deadly and mysterious Worm...

Plot
Part One

The TARDIS lands in Derbyshire woodland, where the locals are hunting a monstrous worm that has been devouring livestock and tourists. Evading the hunting dogs, the Doctor and Leela find themselves on opposite sides of an electric fence.

While the Doctor ingratiates himself with the locals, including wealthy part-time resident Demesne Furze, Leela is attacked by a tank remotely-controlled by the fascistic Colonel Spindleton.

Spindleton has allied himself with the Master, who has made a lair in the caves under Spindleton's manor house. Leela is left to her fate, as the Master summons the giant worm through a wide crack in the ground...

Part Two

Leela escapes into the caverns, and is shown the way out by none other than Demesne Furze.

Furze turns out to be the human disguise of the worm itself - a sentient, dimensionally-transcendental, biological device used to burrow through space-time.

Temporarily consumed by the worm, the Doctor and Leela discover the Master wants to harness it to create a powerful wormhole across space. The worm has refused to do the Master's bidding as the exertion would destroy it.

Generating an electrical storm, the Master succeeds in activating the worm, opening a portal through which his mysterious alien allies can advance onto earth...

Cast

 * The Doctor - Tom Baker
 * Leela - Louise Jameson
 * - Geoffrey Beevers
 * Colonel Spindleton - Michael Cochrane
 * Demesne Furze - Rachael Stirling
 * Carswell / Mercenary - John Banks
 * Julie - Becci Gemmell
 * John - Mark Field

Continuity

 * Leela mentions that she has met Romans. (AUDIO: The Wrath of the Iceni)
 * Leela once again refers to the police as "blue guards." (TV: The Talons of Weng-Chiang; AUDIO: The Renaissance Man)
 * The Doctor refers to the Zygons (TV: Terror of the Zygons), the Krynoids (TV: The Seeds of Doom) and the Axons (TV: The Claws of Axos).
 * The Doctor notes that has a slightly less "putrescent" appearance than when they last met on Gallifrey. This can most likely attributed to his own theory that the Master was able convert the energy from the Eye of Harmony and effectively heal himself, albeit partially. (TV: The Deadly Assassin)