Charlie had difficulty keeping up with Drummond on the slender beach, which was piled with round, sea-smoothed stones that could broadcast their whereabouts.
“While it’s on my mind, I should say that I might know what Fielding meant by those islets,” Drummond said.
“That could come in handy,” Charlie said. He’d presumed Drummond had chosen to keep mum in the presence of Hector. Nice guy and all, but probably a hardcore criminal who would have been less concerned for their well-being once he knew the whereabouts of a weapons system that could net him enough of a fortune to buy this island several times over.
“Do you remember the false subtraction cipher?” Drummond asked. “Yeah. You’re thinking alphanumeric values of ‘Bernadette’ and ‘Antoinina’?”
“Ought to yield the latitude and longitude of Fielding’s hiding spot. I’d need to do the math on paper. But perhaps you can do it in your head.”
With each letter assigned a number based on its alphabetical order, BERNADETTE minus ANTOININA translated to:
As the cipher’s name implies, false subtraction isn’t true subtraction. Charlie worked left to right, subtracting numbers on the bottom line from those directly above. 2–1 = 1, 5–1 = 4-if this were true subtraction, 5–1 would yield 3 because the 1 that comes next borrows from the 5 in order to subtract 4. As for the rest …
“One-four-seven-six-one-three-six-five-four-eight-one-one-six-four,” said Charlie.
“Good.” Drummond nodded. “That gives us latitude and longitude, using decimal values. Latitude of 14.7, longitude 61.3. Or about fifteen nautical miles off the coast of Martinique.”
Bream’s people surely used potent decryption software to parse every permutation of Bernadette and Antoinina, but without the simple cipher Drummond had taught Fielding years ago, they might as well have searched for the mythical treasure of San Isidro. The single-degree latitudinal difference between the 14 and the 13 yielded by actual subtraction equaled 69 miles, a margin of error of some 15,000 square miles.
Charlie was suddenly distracted by the sound of an approaching police boat’s siren-what had been a distant drone became a shriek.
Drummond broke into a jog, continuing to stay close to the seawall, depriving DeSoto or anyone else atop the cliff a glimpse of him. Over the resulting ruckus of stones and clamshells, he shouted, “Now all we have to do is get there.”
Charlie joined Drummond in peering around the edge of the rock wall to see DeSoto on the pier, pacing alongside the bobbing Riva. The real estate agent’s back was to them. They could easily overpower him, if it came to that.
As Charlie followed Drummond onto the pier, DeSoto spun around, the pistol in his hand ignited by the sunlight.
Instinct sent Charlie sprawling onto the hot, splintery slats.
Drummond remained on his feet. Without flinching, he stepped toward DeSoto.
“You best stop right there.” DeSoto’s salesman facade was history.
Drummond continued walking toward him.
“They’ll be here in less than a minute.” DeSoto gestured to sea. The police cutter was now visible, its siren growing louder.
“Give me the gun, please,” Drummond said.
Taking a measure of the older man, in his beach garb and Crocs, DeSoto scoffed. “I suppose you want my ten-thousand-euro reward too?”
Drummond advanced until only the length of the runabout separated them. “I want to avoid hurting you.”
DeSoto aligned the muzzle with Drummond’s chest. “Stop now,” he said evenly.
Drummond took two quick steps, wound back and threw something, some sort of shimmering white disk, too fast for Charlie to track.
The object struck the real estate man in the hip, then dropped to the deck with a clink.
A clamshell.
Glancing down, DeSoto smirked. “That’s all you got?”
His smirk faded when, with one more step, Drummond launched himself into the air. He effectively flew, feetfirst, at DeSoto.
The real estate agent pulled the trigger. The ear-splitting shot scattered birds from unseen perches all over the island. The bullet struck the shore, several small stones leaping upward.
Drummond’s sole smacked into DeSoto’s elbow, causing him to lose his grip on the gun.
Drummond landed on his side, rolled, and sprang back toward the weapon.
The real estate man rallied, snatching it off the slats. He wheeled around and pressed the nose of the gun against Drummond’s neck.
Drummond balled his left hand into a fist and drilled it into DeSoto’s gut. Staggering backward, the real estate agent fired again.
The bullet sent up a water spout fifty feet away.
Drummond heaved a roundhouse into DeSoto’s jaw. The real estate agent sank to the pier. Grabbing the gun on its way down, Drummond regarded him with remorse.
From her hiding spot behind a bush at the top of the clamshell pathway, the young chambermaid shrieked, distracting Drummond. He didn’t notice DeSoto draw a keychain from his trouser pocket and fling it at the darkest blue patch of bay.
Having anticipated this action, Charlie jumped to his feet, sprinted down the pier, and sprang off a rickety slat in what he meant to be a dive. Cold water slapped his face and chest. His momentum carried him down, to about fifteen feet below the surface, where the pressure made his head feel as if it was about to burst.
The key ring was a veritable strobe light in the colorless depths. He snatched it and launched himself upward, breaking the surface to find DeSoto flat on his back, out cold now, and Drummond ensconced at the runabout’s wheel.
Hauling himself over the opposite gunwale, Charlie tossed Drummond the key.
Turning it in the ignition and adding throttle, Drummond glanced at the police cutter, now close enough that Charlie could make out the two men aboard, until, with a boom, the entire craft was obscured by whitish smoke streaming from its thirty-caliber cannon.
A shell screamed toward the Riva.