John Tiggs, mining engineer and munitions expert, tried to get back to the small town of Moose Creek after the first ash fall from the Yellowstone caldera. Instead, he got picked up during a martial law crackdown and thrown in a labor camp. To free himself, he agrees to work for FEMA for six months helping with their rescue and recovery efforts. It is hard and dangerous work, but John finds it emotionally satisfying, knowing that he is making a difference.Nearly two years later, John is finally on his way home to an unknown reception—he let a lot of people down when he left, and now it's time he made it up to them.Meanwhile, Allexa Smeth, Emergency Manager and reluctant deputy mayor of Moose Creek, has her own problems when a band of rogue militants comes to town and tries to seize control. With Colonel James Andrews missing, Allexa must enlist the help of the nearby military base to save her town from an even bigger threat.