Last January, CalTech researchers Mike E. Brown and Konstantin Batygin has discovered Planet Nine using mathematical modeling. With expectations that this true ninth planet will be found in the outer reaches of the Solar System, will this be featured in Blue Planet proper?
If so, then the GTVA will use this as a secret location for massing their fleet for a final strike on Earth in order to integrate Sol into the GTVA, secure its tremendous industrial base for the preservation and re-establishment of the colonies, shatter Sol’s obsolete militaries while largely preserving its manpower and industries to use in defense against the Shivans and unseat the Ubuntu regime and return legitimate GTVA authority to the system.
EDIT: Or will this planet be a location for a major project underway which might serve as a weapon against the GTVA? Or there were dissident elements there who might be receptive to its assistance?