This is the 5th book in the series I think, maybe the 6th. I don't remember for sure, but I do love these characters.
The first book is free and I have made sure to send it to everyone I know. The universe is a ton of fun and the different races all make it even more interesting.
Personally get weird-ed out a little by the GEM, so I was glad they were a main part of this book.
If you haven't read any of the Union station books yet you are really missing out.
This one is about a party on Union station that lasts a few weeks. There are games of chance and skill, art and food. The real fun comes into play when they start judging the competitions. I mean this is union station after all, so nothing is going to go like you think it would. Without giving anything away lets just say some mischievous AI like always are meddling in the affairs of their patrons.