One Man's War (One Man's Island Book 2‪)‬

Seven years ago, a star died in a distant part of the galaxy, sending its deadly gamma rays towards Earth. When the rays reached our planet, they killed virtually all of the human population overnight, leaving only a handful of survivors. Sergeant major Tim Flannery was left to fend for himself in a dead and decaying world.

He thought he'd fought his last battle for humanity on the atoll of Volivoli. Now he only wants to be left in peace, with his new family and a growing new society in northern Arizona.

But he faces another battle. A new evil has risen from the ashes of a dead United States, threatening to take what little he has left and destroy his small enclave. Flannery must again take up arms to preserve what little sanity is left in a world gone mad.