“My sole reason for accompanying you on this afternoon’s excursion,” Inspector Congreve said, “is that I envision a chilled adult beverage awaiting me in some disreputable saloon. I might even order the one thing your great hero did manage to get right—a properly shaken martini.”

“If you had any sense, Ambrose, you’d stop drinking so much and stop smoking that damnable pipe. Wasn’t a six-shooter got the Duke carted up Boot Hill, you know. It was a herd of unfiltered Camels.”

Congreve heaved an audible sigh and removed the old tweed cap from his head. He ran his fingers through his sparse thatch of chestnut brown hair.

Bloody hell, he thought, here was one mystery solved anyway. The precise latitude and longitudinal location where the phrase “Mad dogs and Englishmen go out in the midday sun” had originated. He’d been absolutely barmy to go along with Hawke’s scheme. It was hot as Hades in these godforsaken islands. The obvious notion of removing his woolen bow tie or mismatched tweed jacket and waistcoat never occurred to Congreve.

Notoriously indifferent to his own wardrobe, Ambrose seldom noticed whether his suit trousers and jackets matched and his socks were frequently opposing colors. Wearing clothes appropriate for the season or the weather would simply never occur to him. Ian Baker-Soames, his tailor at Anderson & Sheppard, Savile Row, London, had long ago resigned himself to Congreve’s sartorial eccentricities.

Rara avis, the tailors whispered whenever Ambrose Congreve strode through the hallowed portals of A&S. If he had acquired the reputation of a rare bird, he was blissfully unaware of that distinction.

Hawke was still willfully ignoring his mutterings and pleas, going on and on with his geology lecture.

“That little atoll over there,” Hawke said, continuing despite his audience’s cool reaction. “It’s called Thunderball because of a small blowhole at the top. Bloody thing bellows like thundering gods when the sea blows in hard out of the west.”

“Most exciting, I’m sure,” Congreve said with a yawn.

“Isn’t it?”

“Quite.”

“Hullo, Tommy!” Hawke said suddenly, calling up to the young blond crewman standing guard on the dock. “You might take a quick stroll down the dock and see if our new friends have arrived. Won’t be hard to spot. Bad suits, bad haircuts, and bad neckties. Anything odd catches your eye, give me a quick call on the walkie-talkie.”

“Aye, sir!” Tommy Quick said, and took off down the docks at a run.

“You see, Ambrose,” Hawke said, continuing his dissertation, “Thunderball is completely hollow inside. The sea surges inside, forces the air out the top. Boom! Hear it for miles around, apparently.”

“A true geologic wonder. You’ll forgive me if I don’t hurl my cap into the air and prance about on the tips of my toes?”

“Yes,” Hawke said, too caught up in his enthusiasm to acknowledge the sarcasm. “I swam inside the thing early this morning. Certain aspects of its geology should make it an ideal spot for negotiating with a pair of arms dealers. You’ve got your bathing trunks with you, I assume? We’re going to take these bloody Russians on a little undersea adventure.”

“Arms dealers? Russians? You plainly led me to believe we were meeting some real estate agents.”

“Did I say that? Last-minute change of plans, I’m afraid,” Hawke said, scrambling up the ladder. “It’s cloak-and-dagger time again, old boy. Come along, Ambrose, the Russians are coming!”

Congreve was busy contemplating the shadowy movements of an especially large shark. He leaned over the rail and watched the fish patrolling the clear waters directly beneath the stern of the launch. Going for a swim? Is that what Hawke had said? Congreve considered all forms of athletic endeavor save golf to be sheer barbarism. He heaved what could only be called a wistful sigh. His idea of heaven was puttering and putting around his beloved Sunningdale links just outside London. There, at least, the fiercest creatures one was likely to encounter were surly caddies with apocalyptic hangovers or the odd dyspeptic chipmunk.

He had a standing foursome at Sunningdale, every Saturday morning, rain or shine. Been teeing it up for nearly a quarter of a century. To Ambrose’s great chagrin, he was the only member of his foursome never to have achieved a hole in one. It had become a lifelong obsession. He was hellbent on doing it one day, and—

“That’s a nurse shark, Ambrose,” Hawke shouted from above, interrupting his reverie. “Stop staring at him, you’ll scare the poor bastard to death.”

Congreve looked up and saw Hawke standing next to Quick at the top of the ladder. Hawke said, “Come along, will you? According to Tommy, we’ve still got a few minutes to stroll the docks before the Russkies arrive.”

Congreve grunted something and started wheezing his way up the ladder. He joined Hawke on the dock, pausing to catch his breath.

It was a pretty little cove, really. Four houses perched on stilts just beyond the docks, each one painted a more brilliant pastel shade than its neighbor. Brightly colored fishing boats bobbed on their moorings in waters too many shades of blue to count. Rather fetching, to be honest.

One rainy afternoon in January, about a month earlier, there’d been a long liquid lunch at White’s, Hawke’s club in London. It was there Hawke had first broached the notion of this little Caribbean cruise. Congreve was ambivalent at first.

“I don’t know. How long a voyage do you envision?” he asked. “As Holmes put it so well, ‘My prolonged absence tends to generate too much unhealthy excitement amongst the criminal classes.’ ”

But Hawke wouldn’t take no for an answer and finally got Congreve to agree. After all, it meant an escape from the cold drizzle of midwinter London. Not to mention his tiny Special Branch office in Westminster. A few weeks of “sun, sightseeing, and a bit of shopping” was how the jaunt had been ladled up, and Congreve signed on.

Shopping?

Congreve had hardly been able to imagine what Hawke would want to buy in these godforsaken Bahamian backwaters. An island or two, perhaps? Of course, that was long before he’d learned Hawke was meeting not with real estate agents, but with arms dealers. Congreve looked at Hawke, who’d suddenly stopped dead in his tracks and gone stone silent.

“I’ve been in this harbor before, you know, Ambrose,” Hawke said, his eyes going somewhere else, getting very hard for a moment. “A long time ago. I was just a boy, of course. Barely seven years old. I really can’t remember much else, though.”

“Is that why you chose these particular islands for the meeting?”

“I don’t know,” Hawke said. “It’s odd. It was this mission that brought me here. Obviously. Still, I do feel drawn to the place! I’ve been having these peculiar dreams about these islands that—” He paused and looked away, unwilling or unable to continue.

“At any rate,” he finally said, “I’ve brought along a map. Had it since childhood. A map of a treasure that might be buried somewhere in this neck of the Caribbean. But, to be perfectly honest, I’m not sure it’s the map that’s making me feel—feel like I’m on the verge of something here, Ambrose.”

“Yes?”

“I have no idea what it is,” Hawke said, looking at his friend with helpless eyes. “I just know somehow the map may be a part of the thing.”

“Shrouded in mystery is the term, I believe,” Congreve said, looking closely at his friend.

“Hmm. Yes,” Alex replied, staring at some imaginary point on the horizon. “Shrouded.”

Then he shrugged off whatever feelings he was having and said, “Anyway, it’s as good a place to meet these dodgy bastards as any other, I suppose.”

Constable Congreve put his hand on his friend’s shoulder and squeezed. He had been expecting this moment. Dreading it, actually.