Hank must have heard about the B3 because he greeted Austin with a somber face. “What can I do to help, Kurt?”

Austin unfolded the diagram of the B3 and spread it out on a table. He pointed to the horseshoe-shaped metal swivel that joined the cable to the top of the sphere.

“I need to snag the bathysphere here.” Austin sketched out a hook attached to the end of a cable and showed it to Hank. “Can you put this setup together in less than an hour?”

“Forty-five minutes, tops,” Hank said. “I’ll splice the cable to a spare hook. But, I’ll be honest, I can’t give you something that is likely to last for the half-mile haul back up to the surface.”

“I’m only interested in the first ten or twenty feet,” Austin said. “Once the B3 is clear of the muck, it can trigger its own flotation system.”

“Getting the hook attached to the swivel is going to be tough at this depth,” Gannon said. “The gap between the swivel and the top of the B3 is only a few inches.” He held his thumb and forefinger up. “Like trying to snag something this size from a helicopter half a mile in the air. It would be almost impossible, in my opinion.”

“I disagree,” Austin said. “It would be absolutely impossible. That’s why I’m not going to do it from the surface.”

“How are you . . . ?”A thoughtful look came to the captain’s face. “Bubbles?”

“Why not? She’s been tested to five thousand feet.”

“But . . .”

“Let’s talk about it in the control van,” Austin said.

The box-shaped, twenty-foot-long atmospheric-diving-suit control van was next to the ship’s garage, where the ship’s underwater vehicles and other deep-ocean hardware were housed. The van had a console that was separate from the controls for the ship’s submersibles, and it had a workshop where Bubbles was stored.

Austin and Gannon stood in front of a puffy-limbed, anthropomorphic metal figure that resembled the Michelin man. The transparent dome capping the figure could have come from a bubblegum dispenser.

Bubbles’s technical name was atmospheric diving suit, or ADS, but it was considered an anthropomorphic submersible. A diver using the ADS could go to great depths without having to worry about the killing water pressure or the need to decompress. The bulky life-support system on the back of the aluminum body, or hull as it was known, could sustain the pilot for six to eight hours, or for more time in an emergency.

Bubbles was an experimental ADS owned by the U.S. Navy. It was a successor to the Hardsuit 2000, which had been developed for submarine rescue. The research vessel was transporting Bubbles as a courtesy, then rendezvousing with a Navy ship near Bermuda after the B3 expedition.

Gannon stood with his hands on his hips, vigorously shaking his head.

“I can’t let you do this, Kurt,” said the captain. “Bubbles is a prototype. She hasn’t been field-tested yet. Last I heard, she’s got a for-sure depth limit of only twenty-five hundred feet.”

“Joe would tell you that any engineer worth his salt builds in a huge safety factor,” Austin said. “The Hardsuit 2000 made it to three thousand feet in test dives.”

“Those were test dives, not operational dives. That’s a fact.”

Austin pinioned the captain with his coral-blue eyes. “It’s also a fact that Joe and Kane will freeze to death or die from lack of air if we don’t do something about it.”

“Damnit, Kurt, I know that! I just don’t want someone else dying senselessly.”

Austin realized he had come down too hard and backed off.

“Neither do I,” he said. “So here’s my offer: you get Bubbles gussied up for a dive, I’ll get an opinion on dive limits from the Navy and abide by whatever they tell me.”

Gannon had learned a long time ago that Austin was a primal force, as unstoppable as the east wind.

“What the hell,” the captain said with a lopsided grin. “I’ll get Bubbles ready to go.”

Austin gave him a thumbs-up, and hurried to the bridge. A satellite phone connected him with the Navy’s Deep Submergence Unit in California. He listened with mounting impatience to a recorded directory and spoke with several people before he landed on a junior officer in the unit’s Diving Systems Support Detachment. Austin quickly laid out his predicament.

The officer let out a low whistle.

“I sympathize with your problem, sir, but I can’t give you permission to use the Hardsuit. That would have to come from higher up. I’ll connect you.”

“I’ll deal with the Navy brass,” Austin said with thinly veiled annoyance. “I just want to know if the new Hardsuit can dive a half mile.”

“That’s what the tests were supposed to determine,” the officer said. “The weak spots in an ADS have always been the joints. With the new joint design, theoretically it’s possible to go deeper, maybe to five thousand feet. But if there is one tiny flaw, you could have a massive failure.”

Austin thanked the officer and said he would clear the dive with the officer’s superiors, although he didn’t say when. He hoped to be unavailable by the time the Navy bureaucracy reacted.

While Austin had been discussing the Hardsuit with the officer, a nagging thought had been buzzing around in his head like a hungry mosquito. Heading back down to the ROV control center, he found the young woman who had tracked the ROV still sitting at her station. He asked her to rerun the last sixty seconds of its video. She clicked her mouse and the sea bottom a half mile down appeared on the screen. Once again, Austin watched the ROV soar like a bird over the undulating vegetation covering the seafloor. Its camera soon picked up the splatter from the B3’s impact, then the bathysphere’s dome protruding from the crater.

“Freeze the image right there,” Austin said. He pointed to a dark area in the upper-left-hand corner of the screen. “Now, run it in slow motion.”

The shadow moved off the screen.

The ROV operator stared at the screen, jutting out her lower lip. “I don’t remember seeing that.”

“It was easy to miss,” Austin said. “We were all focused on finding the bathysphere.”

She sat back, folded her arms, and focused on the oblong shape that was barely visible at the edge of the searchlight beam.

“Might be a fish or whale,” she said, “but something about it isn’t quite right.”

Austin asked the operator to enlarge the image. It broke apart as it was blown up, but Austin nonetheless detected a vague manta-ray shape to the shadow. He asked her to print the image, and to play back the final transmission from the bathysphere.

The operator ran off a printout, then reduced the shadow image and tucked it in the upper-right-hand corner of the screen, which now displayed a picture of Kane. He was rattling off an excited description of the luminescent fish swimming around the bathysphere when suddenly he stopped short and pressed his face against the window.

“What was that?” Kane said.

The voice-activated camera switched to Zavala.

“You see a mermaid, Doc?”

Back to Kane.

“I’m not sure what I saw, but I know one thing: it was big!”

Austin snatched up the printout and headed for the aft deck. The big double doors on the garage were wide open, and the Hardsuit had been wheeled out under the crane that would lift it off the deck.

Austin showed Gannon the ROV printout.

“This object was nosing around the B3 when both cables were cut,” he said.

The captain shook his head. “What is that thing?”

“Got me,” Austin said. He glanced at his watch. “What I do know is that the B3 will soon run short of power and air.”

“We’ll be ready in a few minutes,” the captain said. “Did you contact the Navy?”

“A Navy engineer told me that, theoretically, Bubbles could dive to five thousand feet.”

“Wow!” the captain said. “Did you get an okay to use the ADS?”