“It has a current. You could barely feel it, but all the artifacts we found were off to the side, and it moved us in the same direction. It’s a sinkhole over an underground river.”
He looked into her eyes. “Are you saying that’s the gamble you’d like to take?”
She nodded. “If we stay here, we run out of bullets, and we’ll be at their mercy. I don’t want to go that way. I’d rather drown.”
“All right,” he said. “We’ll give it our best try.”
She glanced out over the wall. “The fires are about to the end. I can see the men moving down there. We don’t have much time.”
Sam and Remi hurried down the steps and got their dive equipment ready and changed into their wet suits. Sam brought the waterproof bag of artifacts out of his pack. “Put the guns, phones, and ammo in here.”
While Remi gathered them into the bag and sealed it, Sam put a pair of shorts, a T-shirt, and shoes in the net bag for each of them and lowered their pack into the water.
“That’s everything,” he said. “Maybe they’ll think we got out through the fires.”
Remi shook the bag. “Are you able to carry this?”
“It’ll make a good weight.” He removed the lead weights from his belt and attached the bag to it.
Sam and Remi put on the rest of their dive equipment, held their flashlights, and sat on the edge of the pool. He said, “I’m sorry it comes down to a long shot.”
She leaned over to bump him with her shoulder. “It’s not such a long shot. If there’s one sinkhole, there are probably others. We just have to conserve our air to give us more time to find one. We should have about twenty-five minutes.”
He nodded. As he did, there was a ferocious barrage of gunfire that ran along the top of the wall on three sides, knocking chips and mortar into the air. Sam and Remi turned their heads to kiss. Then they put on their masks, inserted their mouthpieces, and slid into the water. They swam downward for ten or twelve feet and then felt the slow current catch them and begin to push them gently away.
GUATEMALA
Sam and Remi swam cautiously in the deepening darkness, just going with the current for about a hundred feet to make sure that no one standing above the cenote could see them turn on their flashlights, and they increased their speed to move along the stone corridor of the underground river. The water rose all the way to the ceiling of the cavern, leaving no airspace above the surface. At first, the walls were about twenty feet apart but thirty or forty feet deep. Each time the space between the walls narrowed, Sam and Remi would feel a growing dread. When the space opened up a little, their relief was intense.
They kicked their fins steadily to keep their speed up, and the current helped them along. They held their flashlights ahead of them, but what they saw was always the same—more curving tunnel. When the tunnel narrowed, Sam would wonder whether it was merely a fissure in the rock opened up by one of the frequent earthquakes in the region. If it was, it could narrow at some point from twenty feet down to six inches, and they would be trapped and drown.
Sam kept checking his watch as they swam. He and Remi had made a dive yesterday morning that had lasted about fifteen minutes. Each of their aluminum tanks still held about twenty-five minutes of air. That meant that for the first twelve minutes, if they reached an obstacle, they might still be able to swim back to the cenote and surface. Maybe if they did, they’d find that the men who had been after them had already stormed the enclosure, seen they were gone, and left to search for them. Sam knew this thought was part fantasy and part nightmare: the possibility that betting their lives on this underground river might be a dead end.
And then it was thirteen minutes, and he knew that if they tried to swim back, they probably wouldn’t make it before their air was gone. After five more minutes, they certainly wouldn’t.
When twenty minutes had passed, they could count on only five more minutes of air. Even that might be optimistic. They had been swimming steadily, so they had used air at an accelerated rate. He thought about their chances as rationally as he could. There was no reason to believe that they would reach another opening in the ground above them in the next five minutes. Remi was smaller and lighter and used less air than he did. If she had both tanks, she would have twice as much time to find an escape.
Sam shifted his tank to the side so he could turn off the valve, but Remi saw what he was doing. She grasped his wrist with surprising strength and shook her head violently. Sam realized that she must have been thinking the same thoughts, feeling the same fears, and known that Sam would try to give her his tank.
When Remi had grasped Sam’s wrist, his flashlight had swept the space above them, and something had looked different. Now he looked back and upward. He had gotten used to the sight of the bubbles they exhaled rising to the ceiling of the cavern, sliding into a depression, and staying there as a single, gelatinous bubble. Now his bubbles disappeared. He swam upward, with Remi still holding his wrist.
They broke the surface together and aimed their flashlights upward. They were in a dome, with the limestone ceiling about ten feet above their heads. Sam removed his mouthpiece and cautiously took a shallow breath. “The air is good,” he announced.
Remi took out her mouthpiece. They raised their masks and looked around. “I was afraid it would be carbon monoxide or hydrogen sulfide or something from a volcano,” she said.
“Nope. Just air.”
“It’s sweet, clean air,” she said. “How is it getting in?”
“Let’s turn off the flashlights and see if light is coming in.”
They tried the experiment, but there was no light. They waited for their eyes to adjust to the darkness, but they still detected nothing. They switched on their flashlights again. “At least we can swim on the surface for a bit,” said Sam. They closed the valves on their tanks and began to move.
The space remained above them, and they breathed the air and swam steadily along with the current.
Sam paused. “I think I know what this is.”
“You do?” she said.