Like Leela before her, Ace tended to use violence as a means of solving problems, but instead of using a knife, she used cans of a homemade explosive, Nitro9. She met the seventh Doctor and Ace on Iceworld in Dragonfire, where she worked as a waitress after a freak timestorm brought her there. Ace saw the Doctor as a way out of her present existence.

We don't exactly know the circumstances of how she and the Doctor parted company, as the last story, Survival she remains with the Doctor. She does, however leave the Doctor prior to Enemy Within.

Sophie's also reprised her role as Ace in some audio dramas for Big Finish and appeared in Death Comes to Time

Sophie still goes to conventions and is now married and has one baby boy