Cloudy Climes and Starless Skies: A Prosperity Story - Alexis Hall
  This is a beautifully written story of how Byron Kae became the person he is in Prosperity. We also get a glimpse of what has happened to Byron Kae and Dil after the events of Prosperity. I love this story, and Byron Kae remains my favourite character in the series, although they've become a bit less enigmatic.

I'm still not sure how I feel about their sister (one of the MC's of There Will Be Phlogiston) - she's not a very likable character, and this impression has deepened with this story, but on the other hand, her actions could be (at least partially) excused by her youth and parental influence... Still, her behaviour in this book is horrible, and I'm not sure I would've felt for her as much in There Will Be Phlogiston, if I had read this story before.
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