Take for instance, Daughter of the Gods by David K. Barnes, a first and second Doctor story featuring Jamie and Zoe, as well as Steven Taylor, and revolving around a companion with only a single tv episode plus a clip as a visual reference, Katarina.
Most of us will know the story of Katarina's demise in The Daleks' Masterplan and credit must go to the "ideas man" of Big Finish, David Richardson, for the basis of this beautiful yet heartbreaking story.
Creating a multi-Doctor story for an era that we didn't know much about the Doctor could be difficult, but Barnes has done a sensitive job in telling this tale, not only to keep within existing continuity, but he makes the sci-fi and timey-whimey concepts within it easy to understand.
One of the most popular of the early adventures is "The Dalek Invasion of Winter" also penned by the same author. Barnes has a good handle on the era and it's little wonder he was asked to write this one.
Each episode of Daughter of the Gods keeps you wondering what will happen next, with a new revelation to be uncovered and explored after each cliffhanger.
Peter Purves and Fraser Hines are superb as always in their dual roles of both companion and Doctor, taking the listener right back to that era with ease.
The casting of Ajjaz Awad as Katarina is a masterstroke. Together she and Purves create a relationship between Doctor and companion that would have been a pleasure to see back in the 60's, showing just how warm the first Doctor could truly be.
This is not just for fans of the audios. I would recommend anyone who is a fan of the 60's era of Doctor Who take a listen to this.
You will not be disappointed.
Purchase Doctor Who: Daughter of the Gods directly from the Big Finish website on CD or download.