When park ranger Jenna Beck arrives with her search-and-rescue dog, Nikko, to investigate, she discovers that all of the scientist in the lab are dead and every living thing for fifty square miles is annihilated: animals, plants, insects, even bacteria. The land is completely sterile and the blight is spreading. Only one team on earth has the scientific knowledge and military presicion to handle this mission: Commander Gray Pierce and Sigma. As Pierce and his team race to decipher millennia-old secrets, they face their greatest challenge yet: stopping the sixth extinction, the end of humankind.