“You planning on doing some diving, Rex?”

The fifty-two-year-old owner of the Sanibel Treasure Hunters Club glances back over his shoulder. “Why not? Since we can’t do any fishing in this secret spot of yours, I thought I’d get in some night diving.”

“I’m not sure there’ll be much to see.” Iz resumes his place at the captain’s chair. He grabs the binoculars and scans the empty horizon, then verifies their location on the Global Positioning System. “That’s strange.”

“What’s strange?”

Iz deactivates the autopilot and cuts the Manatee’s engines. “We’re here. This is it, the location I was telling you about.”

“Nothing here but water.” Rex twists his long gray hair into a ponytail. “I thought you said there’d be an oil rig.”

“I guess I was wrong.” Iz activates the ship-to-shore radio. “Manatee calling Alpha-Zulu-three-nine-six. Alpha-Zulu, come in. Ead, you there?”

“Go ahead, Manatee. How’s the fishing?”

“Not bad. Mostly yellowtail and dolphin. Rex caught a grouper this morning. Ead, we just arrived at the site above the Chicxulub crater. There’s nothing here.”

“No oil rig?”

“Nothing. But the weather’s perfect, and the seas are calm. I think we’ll stay here for the night while I complete some tests.”

“Just be careful.”

“I will. Call you later.”

The sun is now a molten ball of crimson setting spectacularly off the portside bow. Iz drains the mug of coffee, then activates the boat’s sonar to check the depth of the seafloor.

Just over two thousand feet.

Rex watches Isadore root through a dry-storage compartment. “Hey, Iz, check out your compass, it’s doing the mambo.”

“I know. There’s a massive crater buried beneath the seafloor, about a hundred kilometers across. We’re close to the center point, which possesses a very strong magnetic field.”

“What are you doing?”

Iz finishes attaching an underwater microphone to a large spool of fiberoptic cable. “I want to listen in on what’s happening below. Here, take this microphone and lower it over the starboard bow. Feed the line slowly.”

Iz takes the free end of the cable and connects it to an amplitude modulator. He boots the computer, then plugs in a set of headphones to the acoustics system and listens.

Jesus Christ …

Rex returns. “Microphone’s lowered. What are you listening to? Sinatra?”

Iz passes him the headset.

Metallic churning sounds resembling high-pitched hydraulic pistons and gears cackle into Rex’s ears. “What in the fuck is that?”

“I don’t know. SOSUS detected the sounds a few weeks ago. They’re originating about a mile below the seafloor. I just assumed it was an oil rig.”

“Pretty bizarre, Have you told anyone about this?”

“I filed a report with the Navy and NOAA, but no one has gotten back to me yet.”

“Too bad we didn’t bring the Barnacle.”

“I didn’t know your sub could dive this deep?”