When she and Marty didn’t return to the cavern as scheduled, Jacky and Rad would know something had gone wrong. They would head back to the Oannes. Pip would radio for help.

Elsa’s fragile hope shattered.

Who could help? Cave diving was a niche activity. There were perhaps a few thousand certified cave divers in the world. The number of active divers was much less—and the number of rescue divers would number in the hundreds. So finding volunteers who could help them would be difficult, and even if a group was assembled, it would take days (if not weeks) before they would be organized enough to undertake the rescue.

And by that time it would no longer be a search and rescue; it would be a recovery operation.

When someone is trapped in an enclosed space, they’re exhaling carbon dioxide with each breath, and it’s that increase in CO2, not a lack of oxygen, which ultimately kills them.

The air pocket Elsa and Marty were in was the size of a large garage and probably contained about fifty cubic meters of air. Humans required ten cubic meters of air per day. Double that because there were two of them, and they likely only had two and a half days of air.

Two and a half days.

Elsa heard water move, a small splash. She snapped on the light and scanned the ominous pool. Ripples the size of tractor-tires shimmered on the surface, but whatever had made them was gone.

Can merfolk see in the dark?

Has it been watching me?

Elsa turned off the light to save its battery and sat perfectly still in the overwhelming blackness.

Two and a half days.

Chapter 33

Chapter 33

RAD

The mermaid reappeared a few seconds later. This time it was swimming toward Rad and Jacky, small wavelets trailing behind its neck and grayish shoulders.

“Jesus, Jesus, Jesus,” Jacky said, almost dropping her phone in her haste to open the video app. “Got it! I’m filming it. Oh my God, I’m filming it. I’m filming it.”

Rad didn’t share Jacky’s enthusiasm.

Everything was happening too fast.

Everything felt wrong, very wrong.

She took a step back from the water’s edge and told Jacky to do the same. Instead, Jacky lowered herself to a crouch to capture a better angle of the approaching creature.

“Jacks,” Rad warned again, her voice tight, “get away from the water.”

“Shush!” she hissed. “You’re going to scare it away!”

The mermaid kept coming. Rad made out a fish-like body beneath the water’s surface, undulating, abhorrent. Human-like arms were pressed against its sides. In one hand appeared to be—

“Jacks!” she cried. “It has a spear in its hand!”

“Oh my God, it does!” she said in awe, clearly not appreciating the impending danger. “Marty was right! They use tools!”