The Burning Crown - Stone Blade, #4

Failing a mission can cost Micah Stone his life, nothing new about that, but this time success might cost him his best friend! Of late, the League Navy has suffered a suspicious increase in the number of defective starship parts they receive. These parts fail only during combat, when they're needed most, and often with fatal consequences. Micah, his teammate Vera Kidwell and his old friend John Thompson are sent on an unsanctioned and very under-the-garble mission to find the source of the faulty parts.
The trail leads them inside the League to the Worlds of the Crown of Stars. The Starcrown Sector is a long-time League member-system organized around a feudal government with a King and many Noble Houses. Each of these Houses has its own agenda, enemies and allies, and petty political maneuvering and intrigue are second nature to their members. Micah and his friends must navigate this labyrinth of innuendo, implication, plot and counter-plot in order to locate the ones sabotaging the League.
It is a maze of deception where nothing is as it seems, friends can look like enemies and enemies can be invisible. When the team finally untangles the knot enough to see the path they must travel, Micah makes a horrifying discovery. The only thing standing between him and success is the lives of his friends!