Shadows of Before - Land of Tomorrow, #4

At great cost, the diabolical dictator has been destroyed and the lives of the survivors residing in the Jackson Purchase enclave can finally go about the day-to-day business of simply enduring in their new shattered world. Yet, an evil madman resurfaces with the means to take everything the fragile community has struggled to protect. Even if they do prevail over those seeking to destroy them, the cost might be too much for Nathan and his family to endure.
They know that the murderous chaos that reigns outside their borders may finally break in and destroy everything they hold dear. This is the fourth book in the acclaimed post-apocalyptic Land of Tomorrow series.