The Deep zone

Burned by her own government in a trumped-up scandal, Hallie Leland said she would never return to the world of espionage and its dangerous secrets. But she is unable to resist a shocking summons from the White House. A mysterious epidemic is killing American soldiers overseas and is posed for an outbreak in the United States. The only organism that works as an antidote can be found in only one cave in Mexico. Can Hallie survive drug cartels, federal agents and the normal terrors of caving such as flooded tunnels, chasms, and mind-warping blackness?.