Fight or Die — James Hilton

Brothers Danny and Clay Gunn were brought up an ocean apart. Both served in the military, and both know how to kill, taking work as private military contractors and freelance “fixers”.
When old friends Pamela and Larry are being terrorised by a local gang, keen to scare them away from their beloved business, the brothers step up to help in any way they can. What should be a straightforward job turns ugly when another gang, with a formidable reputation for murder and trafficking, become involved, and suddenly Danny and Clay are thrown into the most trouble they've ever faced.
But the Gunn brothers aren't the type to break promises. They came to fight and if they can't win they'll die trying...