“Nothing tangible,” Lucas replied, his voice so hollow it seemed to come from a distant source. “But knowing that the President and the next three men in line for his office are all in the same place at the same time scares the hell out of me.”

“We’ve turned against the current.” Pitt’s voice was quiet, almost casual, as he stared at the color video screen on the Klein hydroscan sonar that read the seafloor. “Increase speed about two knots.”

Dressed in bleached Levi’s, Irish knit turtleneck sweater and brown tennis shoes, his brushed hair laid back under a NUMA baseball cap, he looked cool and comfortable with a bored, indifferent air about him.

The wheel moved slowly under the helmsman’s hands and the Catawba lazily shoved aside the three-foot swells as she swept back and forth over the sea like a lawn mower. Trailing behind the stern like a tin can tied to the tail of a dog, the sidescan sonar’s sensor pinged the depths, sending a signal to the video display, which translated it into a detailed image of the bottom.

They took up the search for the nerve agent source in the southern end of Cook Inlet and discovered that the residual traces rose as they worked westward into Kamishak Bay. Water samples were taken every half-hour and ferried by helicopter to the chemical lab on Augustine Island. Amos Dover philosophically compared the project to a children’s game of finding hidden candy with an unseen voice giving “warmer” or “colder” clues.

As the day wore on, the nervous tension that had been building up on the Catawba grew unbearable.

The crew was unable to go on deck for a breath of air. Only the EPA chemists were allowed outside the exterior bulkheads, and they were protected by airtight encapsulating suits.

“Anything yet?” Dover asked, peering over Pitt’s shoulder at the high-resolution screen.

“Nothing man-made,” Pitt answered. “Bottom terrain is rugged, broken, mostly lava rock.”

“Good clear picture.”

Pitt nodded. “Yes, the detail is quite sharp.”

“What’s that dark smudge?”

“A school of fish. Maybe a pack of seals.”

Dover turned and stared through the bridge windows at the volcanic peak on Augustine Island, now only a few miles away. “Better make a strike soon. We’re coming close to shore.”

“Lab to ship,” Mendoza’s feminine voice broke over the bridge speaker.

Dover picked up the communications phone. “Go ahead, lab.”

“Steer zero-seven-zero degrees. Trace elements appear to be in higher concentrations in that direction.”

Dover gave the nearby island an apprehensive eye. “If we hold that course for twenty minutes we’ll park on your doorstep for supper.”

“Come in as far as you can and take samples,” Mendoza answered. “My indications are that you’re practically on top of it.”

Dover hung up without further discussion and called out, “What’s the depth?”

The watch officer tapped a dial on the instrument console. “One hundred forty feet and rising.”

“How far can you see on that thing?” Dover asked Pitt.

“We read the seabed six hundred meters on either side of our hull.”

“Then we’re cutting a swath nearly two thirds of a mile wide.”

“Close enough,” Pitt admitted.

“We should have detected the ship by now,” Dover said irritably. “Maybe we missed it.”

“No need to get uptight,” Pitt said. He paused, leaned over the computer keyboard and fine-tuned the image. “Nothing in this world is more elusive than a shipwreck that isn’t ready to be found. Deducing the murderer in an Agatha Christie novel is kindergarten stuff compared to finding a lost derelict under hundreds of square miles of water. Sometimes you get lucky early. Most of the time you don’t.”

“Very poetic,” Dover said dryly.

Pitt stared at the overhead bulkhead for a long and considering moment. “What’s the visibility under the water surface?”

“The water turns crystal fifty yards from shore. On the flood tide I’ve seen a hundred feet or better.”

“I’d like to borrow your copter and take aerial photos of this area.”

“Why bother?” Dover said curtly. “Semper Paratus, Always Ready, is not the Coast Guard’s motto for laughs.” He motioned through a doorway. “We have charts showing three thousand miles of Alaskan coastline in color and incredible detail, courtesy of satellite reconnaissance.”

Pitt nodded for Giordino to take his place in front of the hydroscan as he rose and followed the Catawba’s skipper into a small compartment stacked with cabinets containing nautical charts. Dover checked the label inserts, pulled open a drawer and rummaged inside. Finally he extracted a large chart marked “Satellite Survey Number 2430A, South Shore of Augustine Island.” Then he laid it on a table and spread it out.

“Is this what you have in mind?”

Pitt leaned over and studied the bird’s-eye view of the sea off the volcanic island’s coast. “Perfect. Got a magnifying glass?”

“In the shelf under the table.”

Pitt found the thick, square lens and peered through it at the tiny shadows on the photo survey. Dover left and returned shortly with two mugs of coffee.

“Your chances are nil of spotting an anomaly in that geological nightmare on the seafloor. A ship could stay lost forever in there.”

“I’m not looking at the seafloor.”

Dover heard Pitt’s words all right, but the meaning didn’t register. Vague curiosity reflected in his eyes, but before he could ask the obvious question the speaker above the doorway crackled.

“Skipper, we’ve got breakers ahead.” The watch officer’s voice was tense. “The Fathometer reads thirty feet of water under the hull — and rising damned fast.”

“All stop!” Dover ordered. A pause, then: “No, reverse engines until speed is zero.”

“Tell him to have the sonar sensor pulled in before it drags bottom,” Pitt said offhandedly. “Then I suggest we drop anchor.”

Dover gave Pitt a strange look, but issued the command. The deck trembled beneath their feet as the twin screws reversed direction. After a few moments the vibration ceased.

“Speed zero,” the watch officer notified them from the bridge. “Anchor away.”

Dover acknowledged, then sat on a stool, cupped his hands around the coffee mug and looked directly at Pitt.

“Okay, what do you see?”

“I have the ship we’re looking for,” Pitt said, speaking slowly and distinctly. “There are no other possibilities. You were mistaken in one respect, Dover, but correct in another. Mother Nature seldom makes rock formations that run in a perfectly straight line for several hundred feet. Consequently, the outline of a ship can be detected against an irregular background. You were right, though, in saying our chances were nil of finding it on the seafloor.”

“Get to the point,” Dover said impatiently.

“The target is on shore.”

“You mean grounded in the shallows?”

“I mean on shore, as in high and dry.”

“You can’t be serious?”

Pitt ignored the question and handed Dover the magnifying glass. “See for yourself.” He took a pencil and circled a section of cliffs above the tideline.

Dover bent over and put his eye to the glass. “All I see is rock.”

“Look closer. The projection from the lower part of the slope into the sea.”

Dover’s expression turned incredulous. “Oh, Jesus, it’s the stern of a ship!”

“You can make out the fantail and the top half of the rudder.”

“Yes, yes, and a piece of the after deckhouse.” Dover’s frustration was suddenly washed away by the mounting excitement of the discovery. “Incredible. She’s buried bow-on into the shore, as though she were covered by an avalanche. Judging from the cruiser stern and the balanced rudder, I’d say she’s an old Liberty ship.” He looked up, a deepening interest in his eyes. “I wonder if she might be the Pilottown?”