The Ingenious Gentleman Adric of Alzarius (audio story)

 was the tenth story of the seventh season of Big Finish Productions' Short Trips series.

Publisher's summary
Sir Keeyoht of la Koura, and his loyal squire Adric, are on a quest. A great and noble quest to stop that most vile of Enchanters, the Doctor, from claiming the greatest treasure in the land. Along the way they intend to battle giants (or possibly windmills), inspire adventurers, rescue a princess and ultimately come face to face with that most terrifying of all monsters, the Dragon.

Except Adric knows there are no such thing as Dragons...

Plot
Having lost sight of the Doctor, Nyssa and Tegan after a village a fire, Adric tries to make his way back to the TARDIS and encounters a dragon and is knocked out. He wakes up in a cottage several days later and is told that he is the squire of Sir Keeyoht of la Koura, an adventurer who resembles the Fourth Doctor and invites him on a quest to save Princess Tegan from a wicked enchanter named the Doctor and his sorceress apprentice, Nyssa. Adric accepts and they head off, the Doctor riding his horse, Kaynin, whilst Adric rides a mule.

On the way to another village, Adric questions the existence of dragons given their size and ability to belch fire, which Sir Keeyoht is not able to completely explain. Sir Keeyoht saves the village from six mechanical giants disguised as windmills by causing them to open up with a metal wand stolen from the Doctor, exposing crystals which he and Adric were then able to remove and destroy. During the fight, Sir Keeyoht shouts "Romana", which he later tells Adric is the name of a woman who travelled with him for a time.

Adric and Sir Keeyoht reach the dragon's lair the next day and find the Doctor's blue tower stood outside. Whilst Sir Keeyoht fights the dragon, Adric runs around it to stop the Doctor, who is examining a box of treasure which he identifies as the last remaining Sanchopan Machine, a device which can actualise projections of people's desires. Adric realises that the device, slightly sentient and accidentally damaged by the sonic screwdriver, has been actualising his desire to be with the Fourth Doctor as well as the villagers' desire to be protected and Sir Keeyoht's desire for adventure.

Adric apologises to Sir Keeyoht and accepts that the Doctor is the same man that he began travelling with despite how much he has changed. The Doctor switches the Sanchopan Machine off and all of its creations disappear, after which he leads Adric, Nyssa and Tegan back to the TARDIS. The dragon remains, however, despite Adric believing it to be an impossible creature. Years later, Theresa fights evil and protects the innocent in honour of Sir Keeyoht, who told her the stories of his adventures.

Characters

 * Fifth Doctor
 * Adric
 * Tegan
 * Nyssa
 * Aldonza
 * Keeyoht
 * Theresa

Worldbuilding

 * Sir Keeyoht of la Koura resembles the Fourth Doctor. His horse is called Kaynin.

Continuity

 * Sir Keeyoht defeated swamp monsters, (TV: Full Circle) a vampire lord, (TV: State of Decay) an enslaver, (TV: Warriors' Gate) the Golem of Melkur (TV: The Keeper of Traken) and the Magister at the roof of the world. (TV: Logopolis)