“Do we trust him?” Abrams asked quietly.

“I trust no one. Baruk will remain with him again. But it is not our captain I would be concerned about. If another boat comes, we might not know until we surface.”

Matt was looking over the side at the dark water. “Did I hear someone mention sharks before?”

“Yes, plenty,” Adira said, readying her equipment. “There are great white, bull shark, tiger – all very big and aggressive. But I hear you only need to punch them on the nose, yes?” She looked at him deadpan for several seconds, before breaking into a grin. “I joke – don’t worry about them, Professor. They will not bother us.”

I’m not worried; I’ve faced worse, Matt thought

Adira looked up at the sky and then at her watch. “In about fifteen minutes, the moon will begin to be at its absolute zenith. It will pass through that apex for only about twelve minutes. If there is an opening, and we can find it, and enter it, then we will have less than that to locate the Book and get out.”

“Or we spend the next thirteen hundred years waiting for the next celestial convergence,” Matt finished.

“We can do this,” Tania said.

Matt saw she seemed to be speaking to herself. He checked his own equipment – this time they had headlamps, wrist lights and extra handheld flashlights with a couple of large 35-watt spotlights that could be positioned on stands.

One after the other they dropped over the side, with Andy and Hartogg the first to the bottom, aided by the crowbars they carried. Anyone looking down from above would have seen the white pipes of light moving under the water, and nothing of the black-wetsuited divers behind them.

Matt felt he was holding his breath on the way down. The walls of complete blackness surrounding him made him feel tiny and vulnerable. His scalp prickled, and he couldn’t help feeling he was being watched from somewhere out in the dark.

In a few minutes they were at the island that grew up out of the sand. They broke into two teams – Matt, Andy, and Hartogg, and then Abrams, Tania, and Adira – once again as directed by Adira. Matt could tell she felt the need to keep an eye on Tania. There was quite clearly a great degree of dislike growing between the women, and he doubted it had anything to do with him.

Matt’s team descended into the first crevice and slowly drifted along its ravine walls, slowing now and then to inspect odd shapes or protrusions. After a few minutes they gave up and drifted to the island’s surface.

They swam to the other team’s position, hovering over their split in the seamount. Looking down, Matt could see the pathways of white light, but this time, he could also see the divers as the glow of the full moon was now reaching down into the bottom of the crevice. After another few minutes the divers joined up. Adira looked at her watch, and her frustration was clear.