Deep Shadow

I banged the oyster shell against my own tank, parroting the signal . . . then received a different signal in reply.

Tap . . .TAP . . . tap.

It was Tomlinson. Had to be. Tomlinson, the blue-water sailor, the maritime minimalist. He was attempting Morse code. The man had been studying code for nearly a year, inspired by a late, great friend who had railed against our growing dependence on technology.

I’ve been a devoted user of shortwave radios since childhood, but I’m not a student of Morse code. I know a few basic shorthand signals, but now was not the time to test my skills. We had less than twenty minutes of air left. Subtleties of communication would have to wait.

I returned to my digging, bulling chunks of limestone to the side, then using the oyster shovel to scoop a dent in the sand. I kept at it until a sound within the wall caused me to pause once again.

It was an alarm sound, the rapid clang-clang-clang of a fire bell. Tomlinson was telling me to stop digging.

Why?

I could think of only one possibility: My digging was somehow threatening the stability of the space that was providing them refuge.

Maddening! If I couldn’t dig, how did Tomlinson expect me to free them? After several seconds of silence, he tried Morse code again.

Tap . . .TAP . . . tap.

I forced myself to concentrate. The louder clanks, I decided, were dahs in Morse. The faster, lighter raps were dits.

Tap . . .TAP . . . tap.

Was it the letter R? Yes, an R. R is the most common Morse abbreviation. Even I recognized it. R stands for “roger”—“signal understood.”

It was Tomlinson’s way of beginning a dialogue.

I attempted a dit-dah-dit reply, then waited.

Once again, he tried to signal, but the letters wouldn’t take shape in my head. Because I didn’t understand, I let silence communicate my confusion.

Tomlinson tried a different pattern. I heard: Dit-dit . . . DAH . . . dit. DAH . . . dit-dit- dit.

Three times, he sent it, before I recognized another common Morse abbreviation. F- B. It was short for “fine business”—the equivalent of “everything’s okay.”

Everything was certainly not okay. He was telling me they weren’t hurt—not seriously, anyway. So why had he sounded an alarm?

I tapped out the letter R in reply—“understood”—then listened to a string of louder, methodical bell notes. Instead of attempting to translate, I counted . . . counted four distinctive clangs, but the fifth—if there was to have been a fifth—was interrupted by a cascading clatter of rock and then a thunderous thud.

Another section of lake bottom, or possibly the interior wall of the crater, had collapsed—loosened by our clanging sound waves, more than likely.

I was blinded by another silt explosion, but this time I held my ground. I hung tight to a wedge of rock as the murk enveloped me. For a full minute, I waited for the unstable limestone to settle before I attempted to signal Tomlinson again.

This time, when he replied, the sound was much fainter. Either more sand and rock separated us or his location had changed.

I didn’t want to risk another exchange in Morse code. Sound waves are corrosive, and the lake bottom was too unstable. I needed the jet dredge.

A dredge is the underwater equivalent of a pressure washer. The one we had brought consisted of a generator, a heavy coil of hose that floated on a tractor-sized inner tube and a brass nozzle fitted into a three-foot length of PVC pipe. The thing shot a laser stream of water that would cut through rock and sand and was commonly used for setting pilings—or for treasure hunting. That’s why we’d brought it.

I had to get the generator going, prime the pump and return with the hose. I needed Arlis Futch’s help.

On the chance that Tomlinson and Will had, in fact, found refuge in an underground chamber, I located a crevice below the crater. It took a while to find one that looked to be about the right size. Without removing my BC, I popped a latch on the backpack, freed my air bottle and pulled it over my head. After I had inhaled a couple of deep breaths, I closed the valve, then purged my regulator before removing the pressure gauge and regulator hoses.

Full air bottles sink. Empty tanks float. Mine was half full, so it was easy to maneuver. I wedged the bottle into the crevice, valve up, and braced it with a chunk of rock. When I was convinced the tank was secure, I opened the valve a quarter turn.

A silver chain of air bubbles ascended from the tank. They began to disperse along the underside of the crater. The bubbles became as animated as ants as they probed the rock face, seeking vents and passages to continue their ascent. If there was a chamber above, the bubbles would find the open space and burst free.

I am not a cave diver, although I had explored a couple of caves years ago beneath an island off Borneo. But I’ve spoken with, and read about, Florida’s cave divers—an exacting, dedicated group that has lost more than one comrade to their collective passion for mapping subterranean labyrinths.

From these people, I had acquired a sense, at least, of the complex geology that defines the underwater karst catacombs that exist beneath the flatlands of central Florida. A small rock vent can lead to an ever-narrowing dead end, but it might also open up into a cavern. Caverns have been discovered beneath Florida’s flatlands that are the size of airplane hangars, vaulted cathedrals of limestone. Some were formed during the Pleistocene and had once been home to wandering families, human and animal, before the rising sea level flooded them.

I had heard that such caves might contain air bells—pockets of air—although I doubted the truth of it. Not in Florida, anyway. An airtight vault in rock as porous as limestone? It was unlikely.

Even so, wedging a bottle beneath the collapsed ledge was worth a try. Maybe, just maybe, Will and Tomlinson had been lucky enough to find an air pocket. Maybe, just maybe, I had provided my friends with additional air.

I started up with a few kicks of my old Rocket Fins. When I broke through the surface, I was already yelling for Arlis Futch.

This time, Arlis was waiting. He was standing at the edge of the lake, next to his truck, but his posture was oddly stiff. He was standing as if he were at attention. There were two men with him.

Where the hell had they come from? We hadn’t told anyone about the lake—Arlis had demanded secrecy—and the nearest road was miles away.

I had to clear my prescription mask and square it on my face again before I could be sure of details. Only then did I understand why Arlis was standing oddly. One of the men was holding a pistol to the back of his head.

The second man was also armed. He had a rifle pointed at me.

With his trigger hand, the man was waving me out of the water, calling, “Come up out of there, Jock-a-mo, and meet your new playmates. We got lots to talk about.”

SIX

TOMLINSON’S FIRST LUCID THOUGHT, WHEN HE REALIZED he was pinned under a pile of rock and sand, was an automatic attempt at humor, a comforting cliche: Looks like I picked a bad week to quit smoking.

Not cigarettes, marijuana.

He had promised Ford that he would quit because Will Chaser was on Sanibel for a week, and the biologist was worried the kid would sniff out Tomlinson’s love for the bud.

Apparently, Will had an interest in the subject that went beyond that of a hobbyist. He didn’t need any more