The Enemy Beyond (audio story)

 was the first story in the audio anthology Between Two Worlds, produced by Big Finish Productions. It was written by Andrew Smith and featured Jemma Redgrave as Kate Stewart, Ingrid Oliver as Petronella Osgood, James Joyce as Josh Carter, Tracy Wiles as Jacqui McGee and Mark Bonnar as The Eleven.

Publisher's summary
In a UNIT facility beneath Edinburgh Castle, Kate and Osgood work to unlock the mystery of a stone arch discovered buried in a prehistoric rock formation.

When the arch takes one of their number away to a strange, bleak world, it leads to an encounter with a Time Lord. One with multiple personalities. Soon the Eleven is loose on the streets of Edinburgh and plotting to seize the arch from UNIT by any means necessary.

Plot
to be added

Cast

 * Kate Stewart - Jemma Redgrave
 * Osgood - Ingrid Oliver
 * Captain Josh Carter - James Joyce
 * The Eleven - Mark Bonnar
 * Adam Merchant / Police Officer - James MacCallum
 * Jacqui McGee - Tracy Wiles

Continuity
While discussing with The Eleven about his multiple personalities, Kate realises he is a timelord, of which she notes her dealings with The Master (Master of Worlds (audio story) as well as encountering his female incarnation Missy (Death in Heaven (TV story). She also details that she works with a meddler who is also kind The Doctor (The Power of Three (TV story), The Day of the Doctor (TV story).