Chapter 26

MARTY

In the flooded cavern, Marty and Elsa performed a predive safety check of their equipment, went over their dive plan for the final time, changed into neoprene wetsuits, and geared up.

Marty called to Rad and Jacky, who were filming the cave art with their phones.

“We have three hours of air in our tanks,” he told them. “We’ll use one-third of that for exploring the lava tubes, and another third getting back here, meaning you should expect us in about two hours.”

“What about the last third?” Rad asked.

“That’s in case we get into any sort of trouble,” Elsa said.

“What kind of trouble?”

“Nothing will happen to us, Rad,” Marty told her. “Diving with extra air is a standard safety redundancy, that’s all.”

“Are you sure you want to do this, Marty?” Concern showed in her eyes. “I mean, what if there really are merfolk down there…?”

“I’m counting on it,” he replied, offering her a reassuring smile. He hiked the twin one hundred-cubic-foot steel tanks onto his back, then tossed a black ripstop nylon bag over his shoulder. He picked up the small diver propulsion vehicle (DPV) and fin-walked into the perfectly still water.

∆∆∆

The boulder-strewn cavern slid away as he sank beneath the surface of the subterranean pool. Rad’s and Jacky’s chatter (“See you guys soon!” “Be careful!” “Don’t get eaten!”) faded. Marty clipped one end of the double-braided nylon guide reel to his buoyancy control device (BCD). The other end was attached to an anchor point in the cave so they could find their way out of the pitch-black lava tubes again.

He switched on the diver propulsion vehicle, which was basically a bullet-shaped electric engine that powered a propellor. Since the range they could travel underwater was limited by the amount of breathing gas they could carry, the DPV would allow them to achieve a greater penetration distance in the time they had.

Back on the Oannes, he had devised a tow rope with a large D-ring on one end for Elsa to hold onto. He passed this to her now. She gave him a thumbs up, and he clicked the DPV’s throttle on the stern handlebars. They began moving swiftly forward, the propellor wash parallel to and below them.