As the boat approached the cloud’s periphery, Miller stared at the water and crinkled his brow. The color of the water changed visibly, from green to brown to copper-red. A number of dead salmon appeared in the crimson broth, their silver bellies pointing skyward. Then the fishing boat chugged into the haze.

The men in the wheelhouse immediately felt a change in temperature, as if a cold, wet blanket had been thrown over them. Miller felt a dampness in his throat while tasting a strong acidic flavor. A tingling sensation rippled through his head, and he felt a sudden tightening in his chest. When he sucked in a breath of air, his legs buckled, and stars began to appear before his eyes. His pain was diverted when the second deckhand burst into the cabin with a shriek.

“Captain… I’m suffocating,” gasped the man, a ruddy-faced fellow with long sideburns. The man’s eyes bulged from his head, and his face was tinted a dark shade of blue. Miller took a step toward him, but the man fell to the deck unconscious.

The cabin started to spin before Miller’s eyes as he made a desperate lunge for the boat’s radio. In a blur, he noticed Bucky sprawled flat on the deck. With his chest constricting tightly, Miller grasped at the radio, scooping up the transmitter while knocking over some charts and pencils. Pulling the transmitter to his mouth, he tried to call a Mayday, but the words refused to leave his lips. Falling to his knees, he felt like his entire body was being crushed on an anvil. The constriction tightened as blackness slowly crept over his vision. He fought to stay conscious but felt himself slipping into the void. Miller struggled desperately, then let out a final deep gasp as the icy hand of death beckoned him to let go.

“Catch is aboard,” Summer Pitt shouted toward the wheelhouse. “Take us to the next magic spot.”

The tall, lithe oceanographer stood on the open stern deck of the research boat, dressed in a turquoise rain jacket. In her hands, she reeled in a polypropylene line wrapped around the spool of a mock fishing pole. The line stretched to the end of a guided rod where her prize catch dangled in the breeze. It wasn’t a fish but a gray plastic tube called a Niskin bottle, which allowed seawater samples to be collected at depth. Summer carefully grabbed the bottle and stepped toward the pilothouse as the inboard motors suddenly revved loudly beneath the deck. The abrupt propulsion nearly threw her off her feet as the workboat leaped forward.

“Easy on the acceleration,” she yelled, finally making her way into the cabin.

Seated behind the wheel, her brother turned and chuckled.

“Just wanted to keep you on your toes,” Dirk Pitt replied. “That was a remarkable imitation of a drunken ballerina, I might add.”

The comment only infuriated Summer more. Then she saw the humor in it all and just as quickly laughed it off.

“Don’t be surprised to find a bucket of wet clams in your bunk tonight,” she said.

“As long as they’re steamed with Cajun sauce first,” he replied. Dirk eased the throttle back to a more stable speed, then eyed a digital navigation chart on a nearby monitor.

“That was sample 17-F, by the way,” he said.

Summer poured the water sample into a clear vial and wrote down the designation on a preprinted label. She then placed the vial in a foam-lined case that contained a dozen other samples of seawater. What had started as a simple study of plankton health along the south Alaska coastline had grown in scope when the Canadian Fisheries and Oceans Department had gotten wind of their project and asked if they could continue their assessment down to Vancouver. Besides cruise ships, the Inside Passage also was an important migratory route for humpbacks, grays, and other whales that attracted the attention of marine biologists. The microscopic plankton was a key to the aquatic food chain as it attracted krill, a primary food source for baleen whales. Dirk and Summer realized the importance of obtaining a complete ecological snapshot of the region and had obtained approval to expand the research project from their bosses at the National Underwater and Marine Agency.

“How far to the next collection point?” Summer asked, taking a seat on a wooden stool and watching the waves roll by.

Dirk peered at the computer monitor again, locating a small black triangle at the top of the screen. A HYPACK software program marked the previous collection sites and plotted a route to the next sample target.

“We have about eight miles to go. Plenty of time for a bite before we get there.” He kicked open a cooler and pulled out a ham sandwich and a root beer, then tweaked the wheel to keep the boat on track.

The forty-five-foot aluminum workboat skimmed over the flat waters of the passage like a dart. Painted turquoise blue like all National Underwater and Marine Agency research vessels, it was fitted with cold-water dive gear, marine survey equipment, and even a tiny ROV for underwater videotaping. Creature comforts were minimal, but the boat was the perfect platform for performing coastal research studies.

Dirk swung the wheel to starboard, giving wide berth to a gleaming white Princess Lines cruise ship headed in the opposite direction. A handful of topside tourists waved heartily in their direction, whom Dirk obliged by waggling his arm out a side window.

“Seems like one goes by every hour,” Summer remarked.

“More than thirty vessels run the passage in the summer months, so it does seem like the Jersey Turnpike.”

“You’ve never even laid eyes on the Jersey Turnpike.”

Dirk shook his head. “Fine. Then it seems like Interstate H-1 in Honolulu at rush hour.”

The siblings had grown up in Hawaii, where they developed a passion for the sea. Their single mother fostered an early interest in marine biology and encouraged both children to learn to dive at a young age. Fraternal twins who were both athletic and adventurous, Dirk and Summer spent much of their youth on or near the water. Their interest continued into college, where both studied ocean sciences. They somehow ended on opposite coasts, Summer obtaining an advanced degree from Scripps Institute while Dirk garnered a graduate degree in marine engineering from New York Maritime College.

It was on their mother’s deathbed that they first learned the identity of their father, who ran the National Underwater and Marine Agency and shared the same name as Dirk. An emotional reunion led to a close relationship with the man they had never known. They now found themselves working under his tutelage in the special projects department of NUMA. It was a dream job, enabling them to travel the world together, studying the oceans and solving some of the never-ending mysteries of the deep.

Dirk kept the throttle down as they passed a fishing boat headed north, then pulled up a quarter mile later. As the boat approached the designated target, he killed the engines and drifted over the position. Summer walked to the stern and rigged her fishing line with an empty vial as a pair of Dall’s porpoises broke the surface nearby and eyed the boat with curiosity.

“Watch out for Flipper when you cast that thing,” Dirk said, walking onto the deck. “Beaning a porpoise brings bad karma.”

“How about beaning your brother?”

“Much, much worse.” He smiled as the marine mammals ducked under the surface. He scanned the surrounding waters, waiting for them to resurface, when he noticed the fishing boat again. She had gradually changed course and was now turning south. Dirk noted that it sailed on a circular course and would soon bear down on his own craft.

“You better make it quick, Summer. I don’t think this guy is watching where he’s going.”

Summer glanced at the approaching boat, then tossed the water vial over the side. The weighted apparatus quickly sank into the murk as a dozen feet of loose line was let out. When the line drew taut, Summer jerked it, causing the inverted vial to flip over and fill with subsurface water. Reeling in the line, she looked toward the fishing boat. It continued to turn in a lazy arc barely a hundred feet away, its bow easing toward the NUMA vessel.