Two black Zodiac rafts filled with commandos sped across the channel of the Serpent's Mouth. They had eased out of one of the many mouths of the Orinoco Delta at midnight; after two hours Selene Trujold could just now make out the shape of theYucatan near the gleaming beacon that was theValhalla platform. There was half an hour's worth of water still to cross, the last of it with engines off, moving in silence.

Around her in the rafts, the commandos wore dark suits and carried a stash of black-market weapons, rifles, hand grenades, and explosives. They had night-vision goggles to enable them to direct night operations, but she knew that the Caribbean stars would give them all the illumination they needed.

Her Green Impact fighters were well trained and high-strung, keyed up for this assault, which had been a full month in the planning. Their information had proved correct: the tankerYucatan was lashed to theValhalla 's separate pumping platform during the darkest hours of the night. Though the normal complement of crew members aboard the tanker outnumbered them, Green Impact had both weapons and determination.

And they had a plan, not the least component of which was the element of surprise.

Selene narrowed her eyes and looked around. "We have to time this properly," she said. "We know their routine. During the day, theValhalla needs all of its two hundred crew members aboard. That's why the company gives them time for R and R at night. When the tanker pulls up and begins filling, most of the crew will go over to theValhalla to party with the other workers. During the dead of night, there's only a skeleton crew aboard the tanker. That's when we strike."

Quiet and intent, the members of her force nodded and listened, though they had heard this briefing several times already.

"We are going to hijack theYucatan, get rid of the remaining few aboard. We'll take them prisoner if possible, but don't waste any precious time. Then we disengage the pump and head out. The load should be mostly full by the time we're ready to go. Enough to cause the kind of disaster thatnobody will be able to ignore. If you have any questions, ask them now."

Selene fingered the relic that hung from her neck, wondering yet one more time what it was. Nothing in her knowledge of physics or the related sciences provided any inkling as to its origins. She'd had it embedded in bark and suspended from a strip of leather soon after Manny Sheppard had delivered it and told her of her father's death. The pendant's smooth, irregular edges bit into the joints of her fingers. She rubbed the fragment's slick, strangely greasy surface. It seemed to have a unique combination of heat and ice deep inside it.

Manny's delivery had also contained a note from her father, telling her of the importance of the contents of the package - and of how Frikkie Van Alman meant to abuse his connections and the resources of Oilstar to exploit the secrets it held. Her father's words had left her under no illusion as to who had been responsible for his death: he had dared to defy Van Alman, and had paid for that defiance with his life.

While this assault fit well within the parameters of Green Impact's agenda, she was doing this for him. She was about to cause a financial disaster, a public relations disaster, and an ecological disaster. And it would all be blamed on Frikkie Van Alman. The media would need a scapegoat, and the pompous CEO would be led to the slaughterhouse.

In comparison, theExxon Valdez spill would become a mere footnote in history. And her father would rest more easily.

The Zodiacs roared forward, plowing through the open waters of the Serpent's Mouth. The charcoal black sides of the rafts were large inflated tubes, big enough that even her largest man would have trouble getting his arms all the way around. The tubes angled up and together in the front, forming a point. Between the tubes, a hard fiberglass hull gave the riders a place to sit, and at the rear, the outboard motor was mounted to the squared-off aft of the hull.

Relinquishing her hold on the pendant, Selene balanced against the rubber eyelets of the black raft. Through the hum of the powerful outboard motor and the whisper of the waves, she could hear her father's ghost laughing.

She herself wouldn't laugh until the bloodshed and the horror of the next few hours were done.

Soon enough, the bulwark of the OilstarYucatan loomed up out of the water, surrounded by starlight. Selene and her assault team switched off the motors of their dark Zodiac rafts. From that point on, they approached cautiously and in silence.

The garish display of the monstrous production platform sparkled like the contents of a treasure chest. Selene wished they could do something against that target - thereal target - but her small group had no chance against something as big as theValhalla . There were two hundred people on board. Her group could cause some damage, but they'd all be killed.

On the other hand, if her information was correct and the timing worked out properly, Green Impact could get aboard the tanker and deal with the skeleton crew. Her group would have a chance of survival  - and the oil-ladenYucatan would certainly make a sufficient statement for their cause.

With whispered commands and information communicated through gestures, the two Zodiacs approached the tanker from the rear. TheYucatan sat far from the towering offshore platform, drinking deeply of the crude petroleum that poured down into its holds from the pumping station.

They coasted closer to the stained hull of the ship. Next to her, one of the men stifled an outcry and lunged away from the side of the Zodiac. The large inflatable raft jerked and bumped as something struck it from beneath and swam away, a shadow disappearing into darkness.

"Great white," the man said.

"Fortunately, we're not going swimming," Selene said. "Our business is aboard the tanker."

A couple of men chuckled quietly.

The commandos lashed their two rafts to the lower rungs of the metal ladder on the tanker's hull. Moving like shadows, they climbed to the deck, all but one man, whose task it was to tie the rafts together and move them around to the bow in readiness for the planned escape.

If nothing untoward happened, they could all make it back to the encampment.

In deciding which Green Impact members to take with her from their primary jungle compound, Selene had selected the most dedicated ones, those most ready to follow orders and do what had to be done. These people would be called upon to kill. In an operation like this, she couldn't risk someone flinching or hesitating at the wrong moment.

The Green Impact commandos had studied detailed blueprints of the OilstarYucatan, memorizing every cranny, every deck plate. They had a fairly good idea of where the tanker's remaining crew members would be. Most would be snoozing in their cabins, perhaps grumbling that they couldn't go to theValhalla platform like the others. Captain Calisto would almost certainly be in his private stateroom taking care of small details and reveling in the peace and quiet. He loved his ship and would not be the least bit interested in leaving her for R and R.

The assault team carried their packs of weapons, ammunition, and explosives. Upon reaching the deck, they stashed the more fragile items they wouldn't need until after they'd dealt with the crew. Then they split up, moving in small groups with separate, well-rehearsed objectives.

Selene and three companions marched up to the officers' quarters while the others entered the lower levels of crew cabins, rec rooms, and mess hall. The first muffled gunshots rang out as she reached the captain's private stateroom. The door was partially ajar, so she could see his expression as he whirled around, astonished to hear the weapons fire from below.

Her three companions held out their assault rifles and Selene took a step forward. "I'm sorry about the disturbance, Captain Calisto." Her voice was quiet; commanding. "We need to have a word with you."