Exactly eight minutes after they had left the First Attempt, the bottom began to slope upward, and the water became slightly murky from the surface wave action. A rock formation, covered with swaying seaweed, appeared in the gloom ahead. And then suddenly they were at the base of a vertically sheer cliff that rose at an unbroken ninety-degree angle until it disappeared into the mirrored surface above. Like Captain Nemo and his companions exploring an undersea garden, Pitt began directing his team of marine scientists to spread out and search for the submarine cave.

The hunt took no more than five minutes. Woodson, who had angled a hundred feet out on the right perimeter, found it first. Signaling Pitt and the others by rapping his knife against his airtank, he motioned for them to come and went swimming off along the northern face of the cliff to a point beyond a weed-encrusted crevasse. There he paused and held up a leveled arm. And then Pitt saw it: a black and ominous opening just twelve feet below the surface. The size was perfect; big enough for a submarine or, for that matter, a locomotive to have been driven in. They all hung suspended in the clear crystal water, their eyes fixed on the cave entrance, hesitating, exchanging glances.

Pitt moved first, entering the hole. Except for a few dim flashes of light reflected from the whites of his heels, he disappeared completely from view, swallowed by the yawning cavity.

He leisurely beat the water with his fins and let an incoming swell help carry him slowly through the tunnel. The bright blue-green of the sunlit sea rapidly transformed into a kind of deep twilight blue. At first Pitt could see nothing, but soon his eyes adjusted to the dark interior, and he began to make out a few details of his surroundings.

There should have been a myriad of marine life clinging to the tunnel walls. There should have been darting crabs, winking limpets and barnacles or crawling lobsters, sneaking about in search of tasty shellfish. There were none of these. The rocky sides were barren, and they were coated with a reddish substance that clouded the water whenever Pitt touched the smooth, unnatural material. He rolled face up and inspected the arched roof, watching in fascinated interest as his exhaust bubbles rose and wandered across the ceiling, like a trail of quicksilver seeking escape from a vial.

Abruptly the roof angled upward, and Pitt's head broke the surface. He looked around but saw nothing; a gray cloud of mist obscured everything. Puzzled, he ducked his head back in the water and dove, leveling out at ten feet. Beneath him a cylindrical shaft of cobalt light flowed in from the tunnel. The water was as clear as air; Pitt could see every nook and cranny of the cavern's submerged area.