Liv's origins! She's among my favorite audio companions, but I hadn't head her first story. A very good Seventh Doctor story, a sequel to the Fourth Doctor's "Robots of Death," but it's a good thing Nicola Walker is so good as Liv because this is from the earlier days of Big Finish when women characters were apparently harder to come by.  (They have improved MUCH in the years since, so this is said in light jest.)