Warrior's Code, A

Treachery and double-cross are the hallmarks of the mercenary soldier. Because who is the real enemy? Is it the man in the cross-hairs, or the friend alongside you? Or is it the man who pays your wages? Martin Palmer knows that a potentially fatal bullet might come from any direction. And yet he must fight, because fighting is all he knows. This deadly challenge will test him to the limits of his endurance. He knows there will always be another paymaster with high aspirations, and enough money to pursue them...and money, of course, is the mercenary soldier's creed.
A Warrior's Code by Larry Johns