Renegade: (The Spiral Wars Book 1) by Joel Shepherd is 99c at Amazon may be discounted in multiple countries as also discounted in Germany, check your local Amazon.
Seems to be self published but he has previously published the Cassandra Kresnov Series via Pyr which I read and liked.
http://www.amazon.com/Renegade-The-S.../dp/B0138YJ3WA
AUREALIS AWARD FINALIST; Best SF Novel of 2015
One thousand years after Earth was destroyed in an unprovoked attack, humanity has emerged victorious from a series of terrible wars to assure its place in the galaxy. But during celebrations on humanity’s new Homeworld, the legendary Captain Pantillo of the battle carrier Phoenix is court-martialed then killed, and his deputy, Lieutenant Commander Erik Debogande, the heir to humanity’s most powerful industrial family, is framed with his murder. Assisted by Phoenix’s marine commander Trace Thakur, Erik and Phoenix are forced to go on the run, as they seek to unravel the conspiracy behind their Captain’s demise, pursued to the death by their own Fleet. What they discover, about the truth behind the wars and the nature of humanity’s ancient alien allies, will shake the sentient galaxy to its core.