civilization's fall; future past

Fifteen years have gone by since Merrick Dunn fought and destroyed the creature known as the Feeder. He has since moved to a mountain with his wife Sedonia and they now have two children. General Nash, leader of a southern city using pre-happening tech ask for Merrick's aid to secure some radioactive fuel rods. Merrick declines causing the General to kidnap his children, thinking that now he has leverage to force cooperation with his plans. What he doesn't know is that he has enraged the wrong magic user.