Tom and Lilith are an ordinary small-town couple whose lives are thrown into confusion when an extraterrestrial mold sweeps across the civilized world. As the mold spreads death with its spores, the couple is thrust into a journey to the CDC across an increasingly apocalyptic United States. While Tom is naturally immune, Lilith fights to avoid exposure and contagion. Threats abound and danger lurks in unexpected places, as not everyone is interested in trying to restore humanity to what it once was.