Night Probe!

The sonar operator shook his head. "Dropped straight down."

"Doesn't read like a diver," said Pitt. "The crew probably heaved a bundle of scrap or weighted trash overboard."

"Shall I stay on it?"

"Yes, see if you can detect any movement." Pitt turned to Gu

Gu

"Sonar has a strange contact. I'd like them to make a pass over it." Gu

"The reading is doubtful," Pitt shrugged. "But then, you never know."

As soon as he dropped over the side of the barge, Foss Gly swam straight to the bottom. Dragging an extra set of air tanks with him wasn't the easiest of chores, but he would need them for the return trip and the necessary decompression stops before he could resurface. He leveled off and hugged the riverbed, kicking his flippers with a lazy rhythm. He had a long way to go and much to do.

He had traveled only fifty meters when he heard a sustained droning coming from somewhere in the black void. He froze, listening.

The acoustics of the water scattered the sound and there was no way his ears could accurately detect the direction of the source. Then his eyes distinguished a dim yellow glow that grew and expanded above and to his right. There was no uncertainty in his mind. The Ocean Venturer's ma

There was no place to hide on the flat and barren riverbed, no rock formations, no forest of kelp to shield him. Once the submersible high-intensity beam picked him out, he would become as conspicuous as an escaping convict flattened against a prison wall under the harsh glare of a spotlight.

He dropped the spare air tanks and pressed his body into the silt, imagining the crew's faces pressed against the viewing ports, eyes trying to pierce the unending darkness. He held his breath so no telltale air bubbles would issue from his regulator.

The craft passed behind him and moved on. Gly inhaled a great breath, but didn't congratulate himself. He knew the crew would double back and keep looking.

Then he realized why he'd been missed. The silt had billowed up and clouded his figure. He lashed out with his fins and watched with relief as the submersible's light became lost in a great swirl of sediment. He grabbed up handfuls and waved the ooze about him. Within seconds he was totally cloaked. He switched on his diving light, but the floating muck reflected its ray. If he was blind, so were the men inside the submersible.

He groped around until his hands touched the spare air tanks. He checked his luminous wrist compass for the direction of the Empress and started to swim, stirring up the bottom in his wake.

"Klinger reporting in from the Sappho," said Gu

Pitt stepped back from the monitors. "Let me talk to him."

Gu

"Klinger, this is Pitt. What did you find?"

"Some sort of disturbance on the riverbed," Klinger's voice came back.

"Could you make out the cause?"

"Negative," Klinger repeated. "Whatever it was must have sunk in the silt."

Pitt looked over at the side-scan sonar. "Any contacts?"

The operator shook his head. "Except for a cloudlike smudge this side of the sub, the chart reads clear."

"Shall we return and give a hand with the salvage?" asked Klinger.

Pitt subsided into momentary silence. Oddly, Klinger's query a

Cold logic dictated that the human mind was far less infallible than machines. If the instruments detected nothing, then chances were, nothing was there to detect. Against his own nagging doubts, Pitt acknowledged Klinger's request.

"Klinger."

"Go ahead."

"Come on back, but take it slow and run a zigzag course."

"Understood. We'll keep a sharp eye. Sappho out."

Pitt handed the communications link back to Gu

"Beautifully," replied Gu

The clearing of the gallery was proceeding at a furious rate, or as furiously as was possible under the glue like hindrance of deepwater pressure. The team of divers from the saturation chamber sliced away at the smaller pieces of scrap, working with acetylene torches and hydraulic cutters. Two of them propped up the teetering bulkheads with aluminum support pillars to prevent a cave-in.

The men in the JIM suits were guiding the grappling claw, dangling from the Ocean Venturer's derrick above, to the heaviest sections of twisted debris. While one manhandled the lift cable, twisting it to the best angle, the other man held a small box in his hand-operated manipulator clamps that controlled the huge claw. When they were satisfied that they had a good, healthy bite, the pincers were closed, and the winch operator on the derrick took over, gently easing the load out of what had come to be known. affectionately as the pit.

"At the rate they're going," said Gu

"Four days," Pitt said turning over the words slowly. "God only knows if we'll still be here-" Suddenly he stiffened and stared at the screens.

Gu

"How many divers are supposed to be out of the chamber this shift?"

"Four at a time," replied Gu

"Because I count five."

Gly cursed himself for taking such a foolish risk, but lying under one of the rusting lifeboats he could not observe in any detail the activity taking place down in the hole where the salvage team was laboring. The idea of mingling with them seemed absurdly simple, though dangerous.

He noted there was only a slight difference in the style of his thermal exposure suit and theirs. The air tanks strapped to his back were of an earlier model, but the color was the same. Who would notice a near-lookalike interloper in the murk?

He swam down and approached from one side until his fins scraped against something solid: a steel hatch cover torn loose and resting on the deck. Before he could figure out his next move, one of the salvage crew drifted over and pointed down at the hatch. Gly gave an exaggerated nod of his head in understanding, and together the two of them wrestled the heavy steci plate to the bulwarks and heaved it over the side.

There were no invisible perils here. Gly recognized the threat and kept a wary eye. He pitched in with the others as though he had been doing it from the start. It was to his way of thinking a classic case of the most obvious being the least obvious.

They were much farther along than he had imagined. The NUMA people were like miners who seemed to know exactly where the mother lode was located, and they dug their shaft accordingly. By his calculation they were removing a ton of scrap every three hours.

He kicked across the cavity, taking an approximate measurement of its width. The next two questions were, how deep were they going and how long would it take them to get there: Then he sensed that something was out of place, an impression more fancied than evident. Nothing looked to be out of the ordinary. The salvage men seemed too involved with their work to notice Gly. Yet there was a subtle change.

Gly moved into the shadows and floated immobile, breathing shallowly and evenly. He listened to the magnified underwater sounds and watched the animated movements of the JIM suits. His overworked sixth sense told him it was time to fade away. But he was too late.