I really liked this audio overall.  It's nice to have a strong Liz Shaw story when her role in the Doctor Who franchise is otherwise quite limited.

This story isn't just a good one featuring Liz Shaw, though, it is one that digs into her past, has full segments devoted entirely to her doing stuff, and has a lot of fun ideas for her character.  It really feels like we get a proper sense of backstory here.

The story itself is really fun, too.  We're dealing with espionage, arms trading, and alien technology in a pretty well done thriller.  It definitely meanders a bit in the second half compared to the much more tightly and carefully written first half, but overall it was a good story.  I really liked the angle of this Colonel Matthews charging Liz with treason, and it leads to some very unique interrogation scenes.  At one point, Matthews and Shaw literally switch places mid-conversation, and that was cool to listen to how well they executed this content.

The downside is the ultimate villain and plot are a lot less endearing to me.  It's the same old alien stuff just with some neat added details and layers, like the aforementioned role switching between humans.  When we're dealing with UNIT, it's relationship with the rest of the government, and that sort of stuff around Liz's arrest, I was a lot more compelled.  The alien angle felt mostly unwelcome as the story lost a lot the more we got into that content.  Still I enjoyed this overall and would recommend prospective listeners pick this up when it goes on sale.  Aside from little things like being able to tell Keith Wickham did a lot of the back-up vocals, this is well acted and Tim Treloar, Daisy Ashford, and Jon Culshaw all did a great job impersonating The Doctor, Liz Shaw, and the Brigadier.  Culshaw in particular does a great impression of Nicholas Courtney to the point it felt pratically unmistakable.