It hadn’t worked as planned. Two months after their arrival, the government canceled the program. A week later Matt returned to the States to think things over. Shortly thereafter the relationship ended.

For her part, Kate had become enamored with Papua New Guinea—both its spirited people and its forbidding terrain. She had decided to stay, landing a job as head of internal medicine at Meridian.

Traveling to the Inisi—a tribe the government had placed off-limits decades before to preserve its cultural integrity—could get her fired. She expected a reprimand instead. Where were they going to find a replacement? Prior to her arrival, her position had been open for fourteen months. Besides, her request would likely be approved—though too late to save anyone. One thing was certain: the disease spread rapidly and could be fatal. Such a pathogen, if not contained, could threaten not just the Inisi but the entire interior and beyond.

The only misgiving Kate had about the trip was the presence of her patient. Given her condition upon arrival at the hospital two days before, Abby had no business flying on a medical rescue mission. But once rehydrated and treated for her snakebite, Abby had shown amazing resiliency. Nevertheless, Kate insisted on checking her vitals every two hours on the trip.

The helicopter reached a large tributary.

“We are heading up the Yuat,” the pilot informed them.

Down below, Kate saw a blackish river intersecting a larger, milky brown river. The sediment of the former created a weaving of black and brown for several miles downstream.

They proceeded upstream at a height of four hundred feet. Every five to ten minutes they would approach a smaller tributary, one of which, they assumed, Abby had traveled down. But Abby had no idea which one. The only marker she could describe was a long, dark brown sandbank that was a forty-five-minute walk from her village.

The pilot took the helicopter ten minutes up each tributary. They found nothing.

“Is it possible the trees overhang it?” Kate asked Abby.

“No. It’s open to the sunlight.”

They kept on looking. Ten tributaries. Fifteen.

“We’re going to have to head back soon,” the pilot warned. “We’re almost to the return point on fuel.”

Abby looked worriedly at Kate, who forced a smile. It was little consolation, she knew.

They scouted two more tributaries. No sandbank.

“That’s it,” the pilot announced. “We’re heading back to base.” The helicopter banked sharply and turned to the east.

“No!” Abby shouted into her headset. “Not yet. We have to keep looking.”

“Sorry, ma’am. My fuel light just came on. That means we have just enough to make it back.”

“Can we do one more?”

“Don’t you have an additional fuel reserve?” Kate interjected.

The pilot shot a look at her. “All right. One more.”