The Lost Stars - Shattered Spear (Book 4) - Jack Campbell

The Syndicate Worlds continue to splinter as more star systems pledge allegiance to President Gwen Iceni, General Artur Drakon, and the new government they're establishing at Midway. But the toxic legacy of Syndicate rule continues to undermine their efforts as the rebels encounter difficulty trusting one another and believing their new leaders' promises of freedom from tyranny. Before Iceni and Drakon can put their house in order, they must deal with an even greater threat. An enigma warship has appeared and vanished near a Syndic colony. If the aliens are capable of jumping into other human-occupied star systems, then billions of people could be vulnerable to a hostile invasion fleet anywhere they choose to strike. But an even greater vulnerability lies with Iceni and Drakon, as a once-trusted adviser-turned-saboteur plans revenge...