They put on their tanks again, swam in a wider radius around the pile they’d built, and brought back chunks of limestone that must have been left by other collapses. They didn’t bother to pile the rocks high, just brought them and then went back for more, knowing the air in their tanks must be nearly gone. After a few more minutes, Sam surfaced and took off his tank. Within a short time, Remi surfaced too and took off hers.

“All out?” asked Sam.

She nodded.

“All right. Let me arrange what we’ve got as well as I can.” Sam ducked under the water and moved a large stone and added it to the pile. Remi went under and did the same. Each time they submerged, they held their breath and moved one stone before they came up for air. It was a slow and exhausting process, and their rest periods grew longer, but, little by little, the pile rose nearly to the surface. Sam even built their empty tanks into the pile to add height.

Finally, after hours of work, Sam sat down for a moment. “Okay.”

“Okay what?”

“I’ll lift you up. You’ll stand on my shoulders. You should be able to get your hands up on the rim of the cenote.”

“I’ll certainly try.”

Sam bent his knees. Remi took his hands, stepped lightly on his knees, then stepped up to his shoulders. He straightened his legs, and Remi rose. He could feel her clawing and scrabbling with her hands, trying to pull herself upward on the uncertain surface and failing.

“Step on my hands,” he said. He held them, palms upward, just above his shoulders. Remi looked down, placed a foot on one hand and then a foot on the other.

“Try again,” he said, and she pushed down with her arms while Sam pushed up to straighten his elbows. And then her upper body was on the ground above. She clutched at clumps of plants and dragged herself forward onto the surface.

She looked down at Sam. “I’m up, Sam. I’m out.”

“That’s good news, of course,” Sam said. “I look forward to your weekly visits when you come to drop sandwiches down to me.”

“Very funny,” she said. “What can we use as rope?”

“I’ll use my wet suit,” he said. “I’ll cut it into strips while you look for something solid we can tie it to.”

“All right.”

He couldn’t hear her anymore and knew she had moved off a few feet. He took off the top of his wet suit, took the dive knife from his belt, and began to cut. When he reached the sleeves, he cut each into several strips and tied them together, then tied these each to the long corkscrew shape he had cut from the torso. He took off the bottom of the wet suit, cut it into strips, and added it to the corkscrew.