“Possibly.” Montgomery paused. “But it’s curious, since there have been no reported incidences of cholera in El Salvador in more than a decade. More worrisome are the potential deaths you mentioned.”

“The circumstances do seem strange,” Gunn said.

“Still, I don’t wish to be premature,” Montgomery cautioned. “We’ll know more shortly. Biochemical and DNA testing will confirm exactly what’s in the water. In the meantime, I would check the health of all parties who have been in or around the reservoir.”

“Thank you, Doctor. I’d appreciate it if you can keep me apprised of your findings.”

“I certainly will. I’m glad you and Miss Aguilar turned to us for help.”

Gunn made two more calls. Though it was after five p.m., he had one more task for the day. He took the stairs to the fifth floor and found Hiram Yaeger at his usual post, the curved table in front of the huge video board. He was reviewing code with a pair of young software engineers, and Gunn waited until they returned to nearby cubicles before sitting beside Yaeger.

“Hope I’m not interrupting,” Gunn said.

Yaeger shook his head. “A minor software glitch with our North Atlantic iceberg-tracking satellite system uplink.”

“I just got off the phone with Dr. Susan Montgomery of the CDC in Atlanta. It seems that there is something in the waters of Cerrón Grande Reservoir.”

“Is Pitt in any danger?”

“Doubtful. He’d have exhibited ill effects by now. I left him a message, but he just departed on an overseas flight. I also spoke with the young woman he rescued, Elise Aguilar, and she’s fine. She agreed to see her doctor, just to be sure.”

“What’s in the water?” Yaeger asked.

“Montgomery thinks it could be cholera. She’s waiting for test results.”

“Dirk and Elise would have felt that pretty quick.”

“Agreed.”

“You think it’s something more than that?”

“To be honest, I don’t know what to think. Montgomery indicated there’d been no reported cases of cholera in El Salvador in years. Can you check if there’ve been any other cholera-type outbreaks recently?”

Yaeger was tapping a keyboard before Gunn finished his sentence. The video board displayed a glowing map of the world’s oceans, save for an upper-corner table of Egyptian hieroglyphics. At Yaeger’s instruction, the table disappeared, replaced by the search page.

“What was that?” Gunn asked.

“The inscription on a monument Dirk and Summer found on the bottom of Lake Nasser.”

“I thought they were on their way home,” Gunn said. “I canceled their remaining project work until the Egyptian authorities agreed to provide better security. They and Zeibig were lucky not to have been killed by those tomb robbers.”

“They seem to think there’s something at play beyond artifact theft.”

Gunn shook his head. “Whatever it is, it’s not worth the risk.”

The corner video screen came alive with a list of worldwide cholera outbreaks over the past two years. The deadliest incidences were in Africa, Yemen, Haiti, and India.

“Global cholera numbers have generally be

en receding, but it looks like there’s been a recent uptick. Sub-Saharan Africa has long wrestled with the disease,” Yaeger said. “With the ongoing war, Yemen has had a severe disruption of health and sanitation services. Haiti is still recuperating from its earthquake, while India continues to upgrade its weak infrastructure.”

“Its occurrence in those locations is understandable. Are there any other significant outbreaks of the disease?”

Yaeger tapped his keyboard again. “A number of places have indeed seen an increase in reported cases within the past year. Mumbai, Cairo, Karachi, and Shanghai top the list. I recall a large outbreak in Mumbai hitting the news recently, which was apparently widespread throughout the city.”

“I’m surprised to see Shanghai on the list,” Gunn said.

Yaeger initiated a side search. “According to news reports, it was due to suspected pollutants that weren’t properly treated at a wastewater facility. Fatalities have been ongoing.”