Big Finish squee: "The Chaos Pool"

For the last few months, Big Finish has been running a three-part sequel to the Key to Time.  The Fifth Doctor is conscripted as assistant to Amy, a human-shaped Tracer, and they race Amy's "sister"-Tracer, Zara, on a search for the Key to Time.  The stakes: the fate of the universe (for a change).  When I heard this was being planned, I got all huffy in a "And what was wrong with season 16, precisely?  Aside from all those things that were wrong with season 16?"  But then I heard Lalla Ward was in the final story, and somehow my objections melted away.  Yes, I'm cheap for Romana, what of it?

Anyway, "The Chaos Pool" is the story with Romana (among others), and I listened to it yesterday, and here is my squee.  ( It has spoilers! )