Dethras (audio story)

 was the fourth story in the sixth series of the Fourth Doctor Adventures, produced by Big Finish Productions. It was written by Adrian Poynton and featured Tom Baker as the Fourth Doctor and Lalla Ward as Romana II.

Publisher's summary
In the control room of a World War 2 submarine something strange has started to happen. As the ship runs out of control, its crew begin to fall unconscious...

Finding the submarine in the last place they'd have expected, the Doctor and Romana are confronted by a mystery. Once fully populated, there are now only three men on board. And there's now also a chimpanzee.

What has happened to the rest of the crew? What are the strange noises they can hear outside the hull?

And most importantly, who, or what, is Dethras?

Part one
to be added

Part two
to be added

Cast

 * The Doctor - Tom Baker
 * Romana - Lalla Ward
 * John - Alistair Petrie
 * Flague - Shelia Ruskin
 * Philip - Josh Bolt
 * Robert - Brian Vernel
 * Franklin - John Banks
 * Xankari / Teacher - Jane Slavin

Continuity

 * The Doctor has been bypassing the randomiser for a few journeys. (AUDIO: The Beast of Kravenos, The Eternal Battle, The Silent Scream)
 * Romana states the Black Guardian is bound to find them again. (PROSE: The Well-Mannered War)
 * The Doctor uses his etheric beam locator. (TV: Genesis of the Daleks)
 * Time Lords can survive for a short time in the vacuum of space. (TV: Four to Doomsday)
 * The Sixth Doctor will later encounter Voord that quick-evolve themselves into Cybermen. (COMIC: The World Shapers)
 * The Doctor still wishes to go to Brighton to visit the sea-side. (TV: The Leisure Hive)