A gunshot wound in the middle of the night—the last patient in a long tiring day for Dr. Earl “Illinois” Junker or Doc Junker to the little town of Big Grove, Illinois. The victim—a very drunk Nathan Donaldson with a large hole in his leg—smelled of bad booze. Doc wasn't sure which condition was more life-threatening. It is 1923 and life for Doc Junker is getting complicated. In addition to patients with broken limbs, complicated pregnancies and colds and influenza, Doc Junker senses that the population of is getting sicker—succumbing to ailments that they should survive. Prohibition had spurred a black market trade of liquors and potions that contained a lot more than crude alcohol—heavy metals, opiates and medicinal herbs like digitalis that in homemade concoctions could be dangerous. With the number of illegal speakeasies sprouting up all over the county, the chance of deadly complications was a reality. Now he could add gunplay to the list of hazards the town's people could face. Nate claims he thwarted a burglary, but Doc suspects he was digging for artifacts on someone else's land and was shot for it. There was a cottage industry in the area of archeological digging. Doc knew because it was his hobby too, but he approached his explorations scientifically—Nate was in it for the money. When Doc's friend and patient, Harry Stipes, a local reporter for the paper suddenly takes ill and dies in his arms, Doc discovers an amber flask in his pocket with the name Blue Fire on the label. Harry had been complaining of “seeing yellow” right before he died and Doc suspects that Harry's death is not due to his heart condition at all. Suddenly, the bad feeling that has settled over Doc Junker for the last few months takes a sinister turn—Harry had been working on a story about local bootlegging. Doc Junker starts his own investigation to find Harry's killer and get to the bottom of the mysterious malaise that affects the people of Big Grove.