Mick grabs the journal as the Coast Guard cutter reaches the Jolly Roger’s bow. He hurries back to the stern, releases the winch’s cable—“Freeze!”

Ignoring the command, he jumps down into the protective internal sphere of the eighteen-foot-long minisub, balancing precariously on an iron ladder as he reaches up and seals the hatch. “Take us down, fast!”

Dominique is buckled in the pilot’s seat, trying to recall everything Iz had shown her. She pushes down on the wheel, the minisub submerging—as the keel of the Coast Guard cutter collides with the top of the submersible’s sail.

“Hold on—”

The sub descends at a steep forty-five-degree angle, the titanium alloy plates groaning in Mick’s ear. He leans down and grabs a diver’s air tank as it rolls precariously toward the bow. “Hey, Captain, you sure you know what you’re doing?”

“Don’t be a backseat driver.” She eases the descent. “Okay, now what are we supposed to do?”

Mick squeezes past the ladder to join her up front. “We find out what’s going on down here, then head for the Yucatan coastline.” Mick bends down to take a peek through one of the eight-inch-diameter, four-inch-thick viewports.

The deep blue environment is obscured by a myriad of tiny bubbles rising up along the outer hull. “I can’t see a thing. I hope this tub has sonar.”

“Right in front of me.”

Mick leans over her shoulder to glance at the luminescent orange console. He notices the depth gauge: 344 feet. “How deep can this thing go?”

“This thing is called the Barnacle. I’m told it’s a very expensive French sub, a smaller version of the Nautile. It’s been rated for depths of eleven thousand feet.”

“You sure you know how to pilot it?”

“Iz and the owner took me out one weekend and gave me a crash course.”

“Crash, that’s what I was afraid of.” Mick looks around. The interior of the Barnacle is a ten-foot-diameter reinforced sphere situated within the rectangular hull of the vessel. Data-processing equipment lines the tight compartment like three-dimensional wallpaper. The control station for a mechanical arm and retractable isothermic sampling basket protrudes from one wall, high-tech underwater monitors and acoustic transponders from another.

“Mick, make yourself useful and activate the thermal imager. It’s that monitor above your head.”

He reaches up, powering up the device. The monitor switches on, revealing a tapestry of greens and blues. Mick pulls back on a stub-nosed joystick, aiming the exterior sensor at the seafloor.

“Whoa, what have we here?” The monitor reveals a brilliant white light appearing at the top of the screen.

“What is it?”

“I don’t know. How deep are we?”

“Eleven hundred feet. What should I do?”

“Keep us moving west. Something massive is up ahead.”

Gulf of Mexico
1.1 miles due west of the Barnacle