While this one was a fun, mindless book (well, except the few surprisingly graphic moments) it does not feel like it belongs in this series.
First off, it's set on the moon & in the future
Second, there's no mention of any of the characters or worlds thaf would tie it into the other books
Third, it's about ZOMBIES on the MOON.
That being said, I enjoyed it, there were some unexpected twists, and Ray does a great job narrating, as usual.
But I probably won't revisit this one.