Understanding in his eyes, the lieutenant, who stood halfway through the interlevel hatch, pushed off the rungs, dropping toward her.

Karen yanked the red lever.

Emergency klaxons blared.

The hatch whisked shut.

Karen rolled away as the lieutenant fell through the hatch, kicking at her head. But his attack was halted in mid-swing.

Twisting around, she saw him hanging from the hatch, gurgling, his neck caught in the sliding door. It closed with a pressure meant to hold back six hundred meters of water pressure.

Bones cracked. Blood splattered the deck.

She turned away as his body fell to the floor, headless, twitching.

She ran a few steps away and vomited, remaining bent over, her stomach quivering. She knew she had no other choice. Kill or be killed, Jack had told her once.

Still…

An intercom at the control station buzzed. A voice spoke. “Neptune, this is Topside Control. We’re reading an emergency hatch closure. Are you okay?”

Karen straightened, heart thudding. The Argus must be on its way down. She could not risk being caught. Hurrying to the controls, she frantically tried to remember how to work the radio, moving toggles and dials. Finally, she thumbed the right switch and leaned to the mike. “Topside, this is Neptune. Do not attempt evacuation. I repeat, do not attempt evacuation. The station has been damaged. Implosion imminent. Do you copy?”

The voice returned, somber. “Read you. Implosion imminent.” A long pause. “Our prayers are with you, Neptune.”

“Thank you, Topside. Over and out.”

Karen bit her lip. Finally free, she now turned her attention to more important concerns.

Where the hell was Jack?

9:35 A.M., Nautilus

Jack limped down the last canyon. He spotted lights ahead. It was the crash site! He was so close. He pumped the foot pedals, trying to eke a little more power from the drained batteries. The thrusters whined weakly.

If nothing else, the frantic chase through the seamounts had brought him within a quarter mile of the base. After watching David’s lifeboat implode, it had taken Jack only eight minutes to reach the site. However, his computer screen was riddled with blinking warning lights in hues of red and yellow. Worst of all, the battery power level read zero.

The charge was so low that he’d been forced to turn off all immediately unnecessary systems: lights, carbon dioxide scrubbers, even heaters. After such a short trip, he was already shivering violently, lips blue from the icy cold of these depths.

And now with the lights of the base illuminating the last of the canyon, Jack turned off his sonar. This earned him another half minute of power to his thrusters. He glided the Nautilus forward. The sub’s skids, bent and twisted, rode an inch above the sandy bottom.

At long last he pulled free of the canyons.

After so long in the dark, the lights glared. He squinted. The pillar lay twenty yards to his right, the sea base straight ahead, its three doughnut-shaped sections lit up brightly. He swore under his breath at the distance yet to travel. Why had they constructed the base so far away? He’d never make it.

Proving his words true, the thrusters whined down and stopped with an ominous silence. Jack pounded the foot pedals. “C’mon, not when we’re this damn close!” He managed to earn a weak whine, but nothing more.

He settled back, thinking. He rubbed his hands together, his fingertips numb from the cold. “Now what?”

9:48 A.M., Neptune base

Karen wiped the blood from her hands onto her pants. She had climbed back up to Level 2 after disengaging the emergency lock-down. For the past five minutes, she had been fruitlessly trying to raise Gabriel.

Cut off, she felt blind and deaf. What was she going to do?

She stood up, trying to pace away her nervousness. She considered calling topside and coming clean. The fate of the world depended on someone taking action…anyone. But she knew her chances of convincing somebody in authority were futile. The disk with the data from the Fathom was gone, missing along with the body of Dr. Cortez. And who would believe a woman who had just decapitated a decorated member of the U.S. military?

Karen scratched her head, her heart pounding. There had to be a way.

As she paced, a small temblor shook underfoot. She stopped. The vibrations rattled up her legs. She held her breath. All she needed right now was a deep-sea quake. She moved to one of the portholes. As she peered out, the rattling died away. A fading light caught her eye. It was coming from the pillar.

Karen narrowed her eyes, studying it. Strange.

Suddenly, the light flared up in the pillar. The ground shook again. She gripped the walls, holding herself steady. For the briefest moment, as the light flared, she spotted the glint of something shiny and metallic.

Something was out there.

The quake ended, and the light faded.

She stared, straining, squinting—but could discern nothing more.

“What was that?” she mumbled to herself.

As she stood, arms tight around her, Karen thought of a way to find out.

10:18 A.M., Nautilus

Teeth chattering and weak from stale air, Jack struggled to grab another rock from the silt with the sub’s manipulator arm. Of the first four stones, he had managed to hit the pillar twice. Not bad.

Earlier, as the sub had rested dead on the seabed floor, he’d remembered Charlie’s lesson about the pillar’s sensitivity to energy, even kinetic energy, like something striking its surface. He had just enough battery power to work one of the manipulator arms and lob stones at the pillar. The ground trembled, the pillar flared. But was there anyone to see his SOS? Had the base been abandoned already? He had no way of knowing.

He struggled to dig free another stone. His vision blurred. The cold and the carbon dioxide were taking their toll. As he fought to stay conscious, the manipulator arm froze up. He tugged at the controls. Not enough power.

He tried the radio one last time. The batteries’ remaining dribble of juice was enough to power a final call. “Can anyone hear me? Charlie…anyone…”

Groaning, Jack collapsed back into his cold seat. No answer. He shivered and trembled all over. Waiting. The deep waters had sucked all heat from the small sub. His vision dimmed again. He began to swim in and out of consciousness. He fought it, but the ocean was stronger.

On his last flicker of consciousness, he spotted the large monster bearing down at him…then darkness swallowed him.

10:21 A.M., Neptune base

Karen sat before the control station on Level 1. She manipulated the joystick for the ROV robot named Huey, guiding its arms to grab onto Jack’s sub. On the monitor before her, she watched her work from remote. The grips extended and latched onto a section of the sub’s titanium tubing, clamping tight.

Satisfied she had a firm hold, she backed Huey along the path toward the base. The sub seemed to resist for a moment, then budged slowly. Karen wiped sweat from her eyes. “You can do it, Huey.”

The Volkswagen Bug-size robot continued backing, dragging the sub with it. As it retreated, Karen swiveled the remote camera’s eye, making sure to avoid obstructions while ensuring that she didn’t lose Jack and his sub.

Through the acrylic dome she watched Jack’s form jostle around as the sub was hauled. His head lolled and his arms hung limp. Unconscious? Dead? She had no way of knowing, but refused to give up.

Working quickly, her eyes darted from the screen to the clock on the wall. Her grip grew slick on the joystick. Less than two hours. How could they possibly hope to succeed? On the screen, she watched Huey trundle backward, hauling the dead sub. Either way, she wasn’t going to leave Jack out there.

Struggling with the joystick, she steadily drew the sub along the silt. Luckily, the track between the pillar and the station had already been cleared by workers. Even the stray bits of jet pieces had been vacuumed from the silt. Karen worked as quickly as safety allowed, praying for more time.

Then a familiar voice rose from the control station’s speakers. “Dr. Grace, if you can hear us, please respond.”

Karen cried out with relief. Keeping one hand on the joystick, she used her free hand to patch into the communication system. “Gabriel!”

“Good morning, Dr. Grace, please hold for the Deep Fathom.”

On the monitor, Huey finally reached the station. Karen slowed the robot and carefully pulled Jack’s sub underneath the base. She tilted the camera, coordinating to position the sub under the docking bay doors.

“Karen!”

“Miyuki! Oh, thank God!”

Before her friend could respond, a new voice came on. It was the ship’s geologist, his Jamaican accent giving him away. “Professor Grace, time is of the essence. Have you heard from Dr. Cortez? What is going on?”

Karen gave him a summary as she initiated the docking bay pressurization. The two quickly compared notes. She learned the support ships topside were all leaving, steaming under full power away from the site and abandoning the Fathom. Once they were gone, communications had reopened.

“Why are they leaving?” she asked.

“Gabriel picked up a coded transmission. He was able to decrypt it. Apparently some fail-safe command was initiated. To wipe out the area. It seems they’re not taking any chances on losing whatever resources lie down there to a foreign power. The place has been targeted for a missile strike.”

“When?”

“Gabriel is still trying to work that out.”

Karen suddenly felt faint, light-headed. From how many different directions could death aim their way?

“What about Jack?” Charlie asked.

Karen focused back on the monitors. “I’m trying to get him on board, but I don’t know. The robot can’t lift his sub into the bay. Jack has to do that himself, and I think he’s out of power.”

“I’ll have Gabriel patch you over to the sub. See if you can wake him.”

“I’ll try.”

As she waited, Karen leaned over and peered through the observation window. The bay was flooded and the doors were gliding open.

“Dr. Grace, you are hooked up to the deep-water radio of the Nautilus.”