First Frontier — David A. McIntee

The TARDIS has been split apart stranding Benny is early 20th Century London, Ace on a barren world in the distant future, and the Doctor gone. Whilst trying to work out has happen to the TARDIS (and the Doctor) Benny must deal with grisly murders that make the Jack the Rippers murders pale in comparison and Ace must lead a group of human guerillas against a race of alien, um, bugs.
What better way to flesh out character relationship than to thrust them into an adventure involving just the both of them, (Newer companion Benny and hardened war soldier Ace) without the focal point of the novel (The Doctor) to get in thier way. The most important part of this relationship is Benny seeing Ace's point of view regarding the Doctor's meddling and using her as a pawn in on of his games.