The few things Peta knew about sharks rushed into her mind, like life preservers bobbing to the surface after a wreck. The most relevant thing she remembered was that most sharks didn't want to have anything to do with mankind - or womankind. Even the supposed man-eaters, the great whites, the tigers, and worst of all a rogue hammerhead separated from its pack, dined infrequently on humans.

Eyes locked on the shadowy form of the shark as it grew larger, Peta kicked back. She knew she was sucking her air mixture too heavily. Nitrogen would start building up. That's not a good thing, she told herself, but there was this bigger problem....

The shark that was coming right at her. A blue shark, she guessed, acting completely out of character.

She had two choices: stay perfectly still and hope the shark did a flyby, or do something to make it reconsider its current course. Preferring the latter, she reached down to her thigh and pulled out the rusty dive knife.

The shark was only meters away, resolute in its intent.

Peta held the knife with the handle facing away from her, blade pointing toward her. She pulled her arm close, holding the knife in tight.

There was a theory among divers that hitting a shark on the nose sharply made it back up. Especially, so the theory went, if it really didn't have you in mind for dinner. If it did, the theory was probably useless.

A meter away the shark, a gray bullet now, rocketed right at her chest, its eyes expressionless black dots.

For a moment she thought her arm was moving too slowly to catch it, but the handle miraculously hit the shark directly on its piglike nostrils. If she survived, she'd be sure to tell the experts what they could do with their shark theories.

The creature didn't stop. If anything, the handle acted like a jolt of energy. The blue shark rammed her hard, the force of it shoving her to the side and knocking her regulator from between her teeth. A giant bubble of air exploded from her mouth.

She did a sidearm recovery of her regulator, popped it in her mouth, and sucked in the mixture. When she looked up to find the shark, she saw it trailing away, as if its eyes hadn't seen her at all. A crazy undersea driver, a hit-and-run expert sailing on to his next victim.

Peta hung in the water for a moment to take stock of the damage. Her buoyancy control vest looked as if it had been shredded by the abrasive skin of the shark, but she realized that it had looked the same way when she'd put it on. Undoubtedly, the result of a zillion tourist dives. Otherwise, she was fine, and she was wasting time she didn't have.

She continued her dive down to the hole. To Simon.

Just past 120 feet, she found the bottom.

She was very close to where the drill had entered the seabed. Swimming by, she noticed that the test well itself had been sealed with concrete. The entrance to the cave couldn't be more than eighty feet away. Nitrogen narcosis would normally kick in if she lingered at this depth, but this dive was not about lingering. She had to find the cave and take an express train as deep as it went. Once there she'd have to quickly cut back her oxygen in time to prevent problems. That way at least she wouldn't go crazy with the rapture of the deep. Although, she thought, she could probably do with a little rapture about now.

Right about then, she spotted a tall marking pole left by the drilling team at the edge of an undersea rift. The markers were usually used to track where samples were taken, or places to test for underground oil. In this case, it was a pointer to Simon's destination, the underwater cavern.

She didn't like cave dives, not at normal depth, and certainly not at a tech-dive depth. Once you were inside, your options closed. You lost both light and maneuvering room. One of her best friends once did a deep underwater cave in the Yucatan. They fished him out dead the next day.

She looked at the narrow entrance. Tight, but roomy enough to swim in.

Damn you, Simon, she thought. You should have known better. You shouldn't be in there. You're too old; it's too dangerous.

Time to cut the oxygen - and fast. She reached behind and lowered the oxygen to below 20 percent, while bringing the nitrogen and helium mix up an equal amount. She took a breath. The air tasted a little metallic but otherwise fine.

Finding no further reason for delay, she kicked into the mouth of the cave. Her small light barely caught the walls, and she heard the clank as her tanks scraped the top. The cave twisted and turned, and she tried to check her depth gauge, but there was no room to reach behind and grab it.

She felt the familiar pull of a deep dive: stress, anxiety. It's okay, she thought. Calm down. Focus. No problems here. I'll just hope I have a good air cocktail going for this depth, because if it isn't good, it could be too late for me to tell. Disorientation will hit, confusion, and it'll be underwater mouse-in-a- maze time. And the maze always wins.

Stop it, Peta! Focus! she screamed inside her head.

She came to a fork in the tunnel and looked around. No Simon, no bubbles. Which way to go? One hole narrowed. No way he could have made it through that one. She looked at the other; the walls were smooth, almost polished. That seemed strange. They should have been rough, with coral fingers reaching out like the ones behind her. Instead they looked shiny. She wondered if it could be something volcanic.

She checked her watch as she swam down the strange channel. Ten minutes. That meant Simon had been down what? Fifteen or twenty minutes? He should be on his way back.

Ahead of her, the cave widened into darkness. She kicked slowly, tentatively, up to the mouth of the opening. When she was practically in the opening she became aware of a distant glow.

Using her headlamp to pick up what it could, she saw an enormous chamber, an underwater grotto. A cathedral, but unlike any she'd seen on her own dives or in pictures. It was as if someone had carved a giant, smooth bubble seventy or eighty feet below the seabed.

She shone her light on the glow - much closer now - and picked up another diver.

Simon floated near the far wall. Not moving. Suspended like a lifeless toy in a child's fish tank.

Peta stayed at the entrance to the cavern, looking at the body of the man she'd come to save. Damn it, Simon, she thought. Why didn't you let me talk you out of this?

When she knew she couldn't put it off any longer, she tilted her body and gave a few small fin kicks to sail nearer to him. His lamp pointed down, dully, at the same meaningless spot, but the reflected glow bounced onto the walls. Peta let herself look up for just a moment to see the strange markings on the smooth surface.

They were...she searched for a word.Incomparable . There was nothing she had ever seen that even came close to them. She thought of the markings she'd seen on Mayan tombs, but they were like cave drawings. These weren't primitive. They were stylized, with odd shapes that could have been metallic devices and -  She stopped. There was no time for sight-seeing. She reached out and turned Simon around. His eyes were wide open and had bulged, probably as he struggled to breathe, getting the mix wrong. She checked his tanks. They had plenty of air and looked like they were set to a good ratio of oxygen to nitrogen-helium blend. That meant it must have been his heart. It could easily have given out on him. The tension, the pressure.

Looking down, she saw that he had something clutched in his hand. A sharp chill ran through her. The material looked similar to the pendant that Arthur had given her. She reached out and tried to pry Simon's gloved hand from the object, but his fingers were locked tightly around it. For one grisly moment, she wondered whether she'd have to use her knife to pry off his fingers, but one by one they snapped back like catches on a sunken treasure chest. The object tumbled free, spinning; Peta reached out and caught it.

As her fingers closed around it, she had the same sense of the heat being drawn from her skin as she'd had when she held the piece Arthur had given her. Stranger yet was the fact that the shape looked as if her piece could fit right into it...whateverit was. And she could see places for other pieces to fit, as well.

If McKendry survived and could find Selene and her piece of the artifact, that plus Peta's and Arthur's and the one Frikkie still had could be put together to make - what?

There was no time to think about that now.

She looked to see whether Simon had carried a specimen bag and spotted a mesh bag floating empty around his dive belt. Reaching out, she slowly untied it, taking care not to expend too much energy. That could change her breathing rate and - worse - make Simon's buoyant body spin toward her.

Suddenly, she didn't want to stay in this bizarre cave for another minute. The place gave her the creeps, especially with Simon's body hanging there under the strange wall paintings. Briefly, she debated taking Simon's body with her. According to her dive watch, she had a more than adequate window of time for her return - with or without Simon. Assuming, of course, that she missed the shark on the way.

She stuck the artifact into the bag, thinking, I'm going to leave you here, Simon. I wish I could have made it here in time to stop you, to save you, but you knew the risks. My guess is that this is how you chose to die.

Her contemplation was cut short by the sensation that there was something else in the cavern, and it was coming closer.

Eduardo Blaine watched carefully while Peta's sleek form disappeared into the clear water. He followed her progress until the only sign of her that remained was the scattered trail of bubbles streaming to the surface.

When he was sure she was far enough down not to notice what happened topside, he moved to the front of the boat, peeled off his clothes, and slipped on a wet suit. He looked over at the man on the other boat watching him.

"You can go."

"No, man. Mr. Brousseau told me - "

"I'll bring him back. Don't worry. Of course, if you'd rather wait for the Obeahman to send you an invitation...."

Blaine looked the man right in the eyes. The Trini blinked. He understood the message: Move or die. He quickly turned away and started his boat's engine.

Satisfied, Blaine looked back down at the telltale bubbles on the surface. Assuming the currents weren't pushing them around too much, they told him that Peta was angling away from the support leg and moving toward the center, where the test well would be.

He grabbed a weight belt and slipped on an extra three pounds of metal. He wanted to drop like a stone. If he needed to, he could shed the extra weight on the bottom.

Won't pretty Miss Peta be surprised, he thought, lifting a chest near the front of the boat to pull out his BCV, fins, and an extra pair of tanks.

In minutes, ready to dive, he sat on the railing, rolled backward, and splashed into the water.

He had no trouble finding the cave opening; it had been clearly marked by Charles and Abdul when they'd discovered it. He assumed that Peta was deep inside by now, perhaps all the way into the cavern. Soon, she and Simon would be coming back.

If Simon was still alive.

He reached over his shoulder and adjusted his air mixture, cutting back the oxygen. When he was satisfied with the new mix, he pulled his knife from its sheath and - holding it in front of him like the bill of a swordfish - started into the cave.

Having done more than enough cave diving to know what to expect, he moved smoothly through the twists and turns. He could almost anticipate the bony stone fingers that lurched out from the top and the sides. He swam sleekly, knife held in front of him, dodging the rocky outcroppings.

How long, he wondered, before he'd be in the cave, face to face with Peta and Simon? The two of them would be totally oblivious to his arrival.

Surprise, surprise.

At a fork in the cave, he chose the wider passage. No diver could make it into the narrower one. The walls of this new tunnel were smooth, looking almost preformed, man-made even. Probably created by the flow of water in and out of the main cave.

He saw the dull glow of a light ahead. Instinctively, he kicked harder.

The rocky tube widened suddenly and he shot into the cave. He could only dimly see what was happening. Simon was suspended near the far wall, which was covered by a mural that looked like something from an alien theme park.

Peta floated partially behind Simon's body.

Blaine watched as she took a specimen bag from the dead man's belt and stuffed something into it.

Good, Blaine thought. All the hard work has been done.

He kicked once, twice.

She was turning in his direction. He imagined her shock at seeing someone else in the cave, her relief when she recognized him, and finally her horror when she realized his purpose.

Horror was a bad thing. It was no fun to know that something really bad was about to happen. Better to just go quietly, unaware that - oops, you're dead. Blaine took no pleasure in the horror. Work like this was meant to be done well, but not necessarily savored.

He came at her hard, pushing Simon's body ahead of himself like a battering ram. The panic was rising in her face, and he could see her gulping air as she hit the wall. Not good, he thought. You must breathe evenly when you're diving this deep.

He noticed that his own breathing mixture felt thin and that he was gasping a bit from too much exertion. Unavoidable under the circumstances, he thought. He would check it later.

Keeping Peta pressed to the wall with Simon's lifeless body, he moved his knife in a broad, sweeping arc and expertly cut the main hose from her regulator. Immediately the air mixture rocketed out. He shifted his grip to her BC to steady her as he cut her secondary hose.

She kicked at him. That was another downside of the subject of the work being aware of what was happening. Nothing alivewants to die.

Fortunately the water and the dead weight between them made her slow, inaccurate. It was too late for her as the twin jets of free air shot from her tanks and wedged her tighter between the dead body and the wall.

Blaine sheathed his knife, scooped up the specimen bag, and kicked his way back to the cave opening. He held the bag tightly in his hand, the prize for Frikkie.

A nice prize, with the added bonus that the witnesses would never see the surface again.

Death wouldn't come all that quickly for Peta, but it would come. It was sad, really. She was a beautiful woman with a lot of fire.

He would have liked to have bedded her at least once.