The Caves of Erith (audio story)

 was a Short Trips audio short story read by Stephen Critchlow. It was released as a subscriber-exclusive download, available with subscriptions that included You Are the Doctor and Other Stories.

Summary
It's Christmas, so the Doctor and Lucie spend Christmas in a B&B at a picturesque village, and they find that the village has had a large decrease in childbirth, and then talk to the landlady's son, Oscar, about these almost extinct variety of bats. The Doctor and Lucie wake up next morning to see that Oscar has run off, and find him in a cave. There, he is trying to save a species of bat-people, and they want to reclaim earth by sterilisation...

Characters

 * Eighth Doctor
 * Lucie Miller
 * Oscar
 * Bat-people

Continuity

 * Lucie claims that the Doctor talks about "snogging Elizabeth I". During his tenth incarnation, he would do exactly that in 1562. (TV: The Day of the Doctor)
 * The Doctor mentions that it wouldn't be the first time he's come across a hidden colony of earlier Earth races. (TV: Doctor Who and the Silurians, The Sea Devils, AUDIO: Bloodtide et al)
 * Lucie tells Oscar about "an evil race that covered a planet full of innocent people with thick choking dust". (AUDIO: Blood of the Daleks) After leaving Red Rocket Rising, the Doctor told Lucie that this race was created by a scientist that experimented with people's brains and put them in metal armour. (TV: Genesis of the Daleks)