Shattered union arc (12)
If you want a central plot to follow, this is the arc you should start with.
This arc deals with the general political situation in Sol system from A.D. 9599 to 9670.
This arc is completed.
[Shattered union arc]  [Karin Bau] 
Something to note. When this story was written back in 90s, I, for some reason, believed that planet Saturn was a barren planet. When I eventually found out that Saturn was actually a gas planet, it was years later and it was already too late. Numerous stories and lore were created for the planet to just erase the whole thing.
Therefore, Saturn in Two Clusters universe is a barren planet.