Cate smiled. “Like your coelacanths?”

Mironov nodded, and then turned to his small screens.

The submarine eased past the monolith forest. Everyone’s head turned as they watch them pass by the window.

“That was a close one. We need to keep a lookout, there’s sure to be others.” Jack swung in his seat, finding Dmitry hovering behind Yegor. “I think we need eyes on the sonar screen, permanently, from now on.”

“Aye aye, Captain.” Dmitry rushed to take his seat.

Jack wiped his face with his forearm. “We got distracted – can’t let it happen again. Everyone back to their seats.”

As they sat down and buckled in, Cate felt a pulse move through the skin of the submersible. She felt her stomach do a little flip. “What was that?” She noticed everyone had frozen momentarily, waiting.

Dmitry turned in his seat, head titled as though listening. “Pressure pulse.”

“I felt it too,” Jack said.

There came a soft clang against the skin of the submarine, and then from outside the window, they saw debris come raining down – silt and stones, most no bigger than a fist.

“I think there‘s been a pretty good sized tremor down here.” Jack leaned forward, looking up from under the curved window, and then out over the seafloor. “Most of the beasties look to have headed home.”

Greg snorted. “You’d think they’d be used to that – living in a giant cave I mean.”

“Maybe they are,” Abby said. “And that’s why they’ve learned to get the hell out of here when the rocky rain starts to fall.”

“Let’s hope no big pieces, yes?” Yegor said slowly.

“Very, yes,” Greg responded.

They continued on, the grasses now strewn with what looked like snow from the overhead rain of debris. However it didn’t take long for small crustaceans to reappear from their nooks and crannies and begin to pick over the new morsels of moss and lichen on the fallen rocks.

“I think… something,” Dmitry said.

Jack half turned. “You got something back there?”

“A ghost maybe – strange. I thought I saw big sonar shadow.” Dmitry exhaled through his nose. “Gone now. But there is a geology change coming up.”

“Ahead slow, Yegor.” Jack leaned one arm over the chair. “What have you got?”

“Cliff coming up – five hundred feet to starboard,” Dmitry responded, head down over his screen.

“Barrier wall?” Jack asked, and turned back to the window.

“No, a cliff, and we are on top of it. Deep water, falling away to depths,” Dmitry responded.

Jack eased Prusalka back another few knots. Out of the window, they could see the fields of grasses and sea life began to disappear, and then the seafloor became a barren plain of dark rock. In another hundred feet, the bottom just ran out and fell into a darkness their powerful light couldn’t hope to penetrate.

“Very deep,” Yegor said.