"Thomas Hudson looked at the sky and saw the long white hackles of clouds of the east wind. Then he looked ahead at the point of the main key, at the spot of key and the flats that were beginning to show. There he knew his trouble would start."

– Ernest Hemingway, 'Islands in the Stream'

We need a boat. It seems reasonable that a marina would be a good place to start. There's a dock, a row of four charter fishing vessels, and the ultramarine Caribbean lapping at the pier. Photographer Antonin Kratochvil and I are even holding a reservation slip with our names and today's date on it.

Yet commandeering a ship in the only communist nation in the Western Hemisphere – where on the eve of his 80th birthday, the president is sickly and half his constituents would gladly swim the 90 miles to Key West – is proving troublesome. We've been sitting in our rental car for three hours, very much on land and very hot. As two portly cops circle us in a tiny Russian-made police car, I wonder if our 1,500-mile pilgrimage to find the island where Hemingway ended his last novel has come to an abrupt halt.

"Papa would've found a boat, asshole," Antonin says. His other pet name for me is "shithead," or, in his Czech-accented English, "sheethead." On very special occasions, like when I lure a young female traveler back to our hotel or when I manage to avoid wrecking our rental car in a pothole, he combines the two: "Way to go, asshole-sheethead!"

With four marriages and 30 years of war-zone photography under his belt, Antonin stands as the closest facsimile to Hemingway I've found thus far. Which is to say he knows how to stay alive in a foreign country, is ornery as hell, and makes the perfect partner with whom to search for the elusive Cayo Contrabandos.

The island is one of 2,500 in Cuba's remote Jardines del Rey archipelago, a stunning string of keys off Cuba's northern coast some 300 miles east of Havana; it is also the setting for the closing scene of Hemingway's last novel, 'Islands in the Stream.' The Jardines were Hemingway's favorite getaway during his 30-year love affair with Cuba, and they were also the site of his storied World War II submarine-hunting mission, during which he outfitted his fishing boat with U.S. Navy-issue machine guns, hand grenades, and explosives, and set out to sink a German U-boat.

When he sat down to write 'Islands in the Stream' after the war, Hemingway reimagined the mission through the eyes of his alter ego, the stoic painter-warrior Thomas Hudson, who heroically pursues a crew of shipwrecked German submariners in the Jardines. The book is a wild exaggeration of Hemingway's real-life 1942 operation, in which Papa and his crew passed the time playing poker, drinking rum, and tossing hand grenades at sharks. In the final scene Hudson, who like Hemingway suffered from manic depression and was frustrated at being sidelined in WWII, takes a machine-gun blast to the chest in an ambush off Contrabandos. The scene is masterfully rendered, and it eerily foreshadows Hemingway's own death by shotgun. It also made me wonder if finding the island might shed some light on the mystery and tragedy that enshrouded the end of Hemingway's life.

'Islands' proved to be a monster of a novel that Hemingway never finished. His fourth wife, Mary Welsh, found the manuscript in a bank vault in Havana after Hemingway's suicide in 1961, and she had it published in 1970. In his manic editing of the book before he died, Hemingway had removed two sections unrelated to Hudson's sub hunt. One of those became a slim volume called 'The Old Man and the Sea,' which clinched his Nobel Prize in 1954.

Then he returned to work on 'Islands,' his homage to the palm-fringed fishing paradise where he spent some of his last best years and a perfect blueprint for two closet Hemingway junkies like Antonin and me to bird-dog Papa's last great adventure.

Which we are set to complete, if only we can find a boat, a point Antonin makes roughly every 15 minutes. What I haven't told him is that every person I've interviewed on the trip has suggested that the conveniently named Contrabandos may well be one of the few details in 'Islands' that Hemingway made up.

Tracking Hemingway in Cuba is like probing Graceland for signs of Elvis. In any building that stands the slightest chance of hosting a tourist, his image is more ubiquitous than Fidel Castro's. We spent our first three nights at one of Havana's most prominent Hemingway shrines, the flamingo-pink Ambos Mundos Hotel, in which he penned 'For Whom the Bell Tolls' during the 1930s. Papa paid $2 for room 511 on his first night in Cuba in 1928 and kept the room for more than a decade, until he bought Finca Vigía (Lookout Farm), outside Havana, in 1939.

I took in the hotel's photographic ode to Papa our first night as Antonin gleefully pulled on a Cohiba Robusto in the open-air lobby. The collage documented Hemingway's time in Havana in reverent detail: Papa in front of his boat, the Pilar, with one of 52 marlin he caught in the summer of 1933; at the gold-friezed Floridita restaurant where he entertained Errol Flynn, Gary Cooper, and Spencer Tracy; with the captain of the Pilar, Gregorio Fuentes, on whom he based the protagonist in 'The Old Man and the Sea.' (Fuentes died in 2002 at age 104.)

All Hemingway trails eventually lead to a bar, so on our second afternoon we sidled up to one of Papa's favorites, the seedy Dos Hermanos on Avenida del Puerto. The Spanish poet García Lorca and Al Capone also favored the mahogany-trellised joint. As the sun dropped behind the colonial mansions of Old Havana in a heavy yellow mist and musicians walked in off the street to join the band, an aging barkeep served us cool mojitos with fresh mint and bitters.

The Dos Hermanos and the Floridita, the bar Hemingway made famous by downing 12 daiquiris, its flagship creation, in one sitting, served as the unofficial headquarters for the sub-hunting mission. During just the first half of 1942, German U-boats sank 397 Allied freighters in the Atlantic and the Caribbean, causing George C. Marshall to proclaim the entire war effort to be in jeopardy. Beginning in June 1942, the U.S. Navy mustered some 2,000 private yachts to "passively" patrol the East Coast and Gulf of Mexico, from Maine down to Texas.

Hemingway had already been heading an antifascist spy ring at the behest of American ambassador Spruille Braden. Now Papa volunteered the Pilar for sub-chasing duty and took the civilian patrols a step further by convincing the Office of Naval Intelligence to outfit the fishing boat with Thompson machine guns, hand grenades, a radio, a bazooka, and all the government gasoline she could take.

The general scheme of "Operation Friendless," named for one of Hemingway's cats, was to lure a U-boat alongside with the promise of fresh food and water. When the crew emerged, the sub hunters would open fire and throw explosives-packed fire extinguishers down the U-boat's hatch. The Pilar would then radio Guantanamo Bay and a navy frigate would fish the survivors from the sea, elicit communication codes from them, and wipe out the German undersea fleet. Simple.

The weathered teak decks of the 38-foot Pilar didn't appear up to the task when I inspected them the following day at the Finca. The boat now sits on the tennis court of the Hemingway estate, which has been preserved as a national museum. Through a stand of palms I watched Antonin snoop around the pool in which Ava Gardner reportedly swam naked. On top of the hill sat Papa's colonial home, the southwest corner holding the room in which he typed Islands and scripted articles for 'Colliers' for $1.25 a word. As I inspected the rickety wet bar Hemingway had rigged on the Pilar's flying bridge, the idea of broadsiding what was then the world's most advanced fighting machine with a wooden fishing boat seemed absurd, if not insane.

Hemingway knew this on some level, so he assembled a nervy crew to man the Pilar's first three-month patrol. The core came from his "Crook Factory" of spies – "a bizarre combination of Spaniards: some bar tenders; a few wharf rats; some down-at-heel pelota players and former bullfighters," by Braden's account. In addition, the roster included businessman Winston "Wolfie" Guest, Fuentes, two Basque jai alai players nicknamed "Paxtchi" and "Sinsky" (to throw the grenades), and a marine communications expert named Don Saxon. When Papa's children visited, they joined in as well.

Hemingway carefully maintained the Pilar's cover as a research vessel (which he used in 'Islands' as well), writing to his son Patrick, "All the scientific projects are in fine shape and everything will be okay with them." The scientific research made it imperative to keep fishing lines in the water at all times. So on November 20, 1942, as a slightly batty Hemingway motored the Pilar past the embattlements guarding Havana Harbor, the world's greatest and most heavily armed fishing trip was about to begin.

On a cool spring day with the trade winds whipping whitecaps across the Bahía de Perros, it's obvious what drew Hemingway to the palm-crowned islets of the Jardines. The keys range from the size of a traffic circle to 4,000-acre Cayo Romano, and many are interconnected by shifting shoals and sandbars. They appeared, he writes of the archipelago, as a "line of green keys that showed like black hedges sticking up from the water and then acquired shape and greenness and finally sandy beaches."

The chain officially begins in the province of Matanzas and stretches 289 miles southeast to Camagüey. The area is a waterman's Eden, with more than 1,000 marked dive sites and enough anchorages and beaches to explore for months in a yacht or sea kayak. The nearby coral reef is one of the largest continuous reefs in the world and shelters some 900 species of fish. The waters bordering the Old Bahama Channel are known to offer some of the best deep-sea fishing in Cuba, while the inshore flats harbor mythically large bonefish.

Hemingway had been exploring the Jardines for years, since buying the Pilar in 1934 for $7,455 from Brooklyn's Wheeler Yacht Company. The boat was constructed with an oak frame and equipped with a custom fighting chair, a 75-horsepower Chrysler engine for cruising, and a 40-horsepower Lycoming for trolling. 'For Whom the Bell Tolls,' published in 1940, had made Hemingway into America's most celebrated writer; it was to Cayo Romano, Cayo Guillermo, Cayo Coco, and the islands around Nuevitas where he went to escape his newfound fame. ("Book selling like frozen daiquiris in hell," he wrote to his first wife, Hadley Mowrer, in January 1941.)

Papa researched many of the 'Islands' passages with his lover, Jane Mason, a notoriously wild millionairess. Fishermen say he'd hole up with her in a shack for days, leaving only in the afternoon to hunt birds with a shotgun while Mason collected seashells. Fishing and boating were also a salve for his gnawing depression, and he took to them passionately, losing himself in the Jardines for months at a time, getting to know local fishermen and collecting material for what would become his most famous and most puzzling novels.

From Havana we follow roughly the same course Hemingway did on his voyages to the Jardines, albeit on land in a Czech Skoda station wagon. Instead of navigating reefs and squalls, we dodge livestock, suspicious police, and wizened farmers peddling blocks of salty cheese in the middle of the six-lane A-1 highway. Between comments on my erratic, hungover driving, Antonin tells stories of being taken hostage in Afghanistan and following the U.S. invasion of Iraq via Kuwaiti rental car. He refused to be embedded, and on several occasions came close to getting killed.

As we approach the Jardines, we can see that much has changed since the Pilar sailed here. The most dramatic transformation came when Soviet subsidies dwindled and Castro turned to tourism to fill the void. In 1988, the first of a network of pedraplenes ("roads on the sea") was completed to Coco, and over the next 10 years 3,000 rooms went up on Coco and neighboring Cayo Guillermo. To visualize our base at the Tryp Cayo Coco, one of 11 "all-inclusive" resorts on the two keys, imagine Captain Merrill Stubing T-boning the Love Boat into Gilligan's Island, building wooden staircases to the beach, and hiring a crew of hyperactive dance instructors to yell at guests 14 hours a day through remote headsets. With 502 rooms, six restaurants and bars, a discotheque, gymnasium, amphitheater, tennis courts, free drinks 24 hours a day, and the best Tom Jones impersonator in Latin America, the Tryp stands as a testament to Castro's Vegas envy.

After one dispiriting night there, we escape with a fly rod. Our fishing guide, Orlando Gonzales, meets us outside a neighboring hotel with a neatly packed backpack and a shirt advertising Coco's "Parque Natural," a scruffy brush patch on the island's old airport. Thanks to Castro's intense paranoia, maps in Cuba are almost nonexistent, and asking directions, even from locals, often leads to more questions than answers. (A car rental agent aptly named Morón told us a two-hour drive would take two days.) Lucky for us Gonzales navigates by watching the ocean, and he leads us directly to the yellow-and-black-checkered Diego Velázquez lighthouse by which Hudson and Hemingway navigated the archipelago.

"[Hudson] looked up at the white-painted house and the tall old-fashioned light and then past the high rock to the green mangrove keys and beyond them the low, rocky, barren tip of Cayo Romano," Hemingway writes.

We can see Romano from the lighthouse's parapet, as well as 5,000 square miles of ocean and beach that Cuba's tourism boom hasn't touched. From the tip of Cayo Cruz to Coco and Guillermo, the water between the keys deepens from aquamarine to green-blue to navy. On the horizon, towering thunderheads ink the ocean black beneath them while breakers billow in front of a lone tanker cruising the Old Bahama Channel.

The lighthouse signaled the beginning of Hudson's final pursuit of the Germans. It also marks the end of our bonefishing expedition, when it turns out that we'll have to traipse across sharp coral and hot sand, on foot, under the broiling sun, all in order to catch an inedible fish. Our enthusiasm wilts, and we bid Gonzalez (and our $75) farewell.

We follow Hudson's/Hemingway's trail farther the next day, to the cut between Coco and Guillermo where the Germans supposedly passed. A bridge now spans the gap, and we continue along Guillermo, searching for one of the beaches Hemingway and Jane Mason frequented on their trysts. Instead, we find a Disneyesque gas-powered locomotive, dispatched from one of the resorts, marking the entrance to Playa Pilar. While Antonin browses the last chapter of Islands under a palapa, I explore the rocky point at the northwestern tip of Guillermo.

We've been starving all week, thanks to several poorly thought-out laws Castro imposed to foster tourism. Every piece of food a tourist eats must be inspected by the government, and thus sits in a warehouse, getting stale, for at least a week. Fishermen can only keep the head and tail of any fish they catch; the meat must be turned over to the state immediately. And Cubans are not allowed to eat lobster, to ensure that officials have enough frozen, rubbery tails to serve to tourists. So it is more with a sense of appetite than sport that I notice a school of plump Cuban jacks swimming off Guillermo.

An hour later I'm back, fly rod in hand, clambering 30 feet down a razor-sharp coral cliff to cast for dinner. When a dachshund-size tarpon removes my fly with a flick of its head, I opt to join a Spaniard who has arrived with casting gear and a bucket of Rapala lures.

Over the next two hours, I take part in a Monty Python version of 'The Old Man and the Sea.' It takes Pedro two casts to hook his first 30-pound tarpon, but then the oafish hotel manager almost expires reeling the beast in. Twenty minutes and several thrilling tail-walks later, he finally wrestles the fish to the edge of the cliff, at which point he explains in a frighteningly high-pitched wheeze that it's my job to scale down to the water's edge and gaff the fish one-handed. Soon after, he reels in a second 30-pounder, collapsing dramatically on the ground as I lug it, too, up the cliff. I have a brief respite when he hooks a mere 15-pound barracuda, but I'm soon faced with the most difficult endeavor of the afternoon: hefting the 75-pound catch back to Pedro's Audi, where he hurriedly bids adieu and zips back to his hotel with all the fish in his trunk.

After a week in the surrealistic world that is Castro's Cuba, I am beginning to think that Cayo Contrabandos might not exist. Meanwhile, Antonin has begun explaining to complete strangers the improbable factors that miraculously aligned to make me into an asshole and a shithead simultaneously. Thankfully the manager of the marina signs an inch-thick ream of paperwork and nonchalantly nods his head toward a boat tied to the pier. A second miracle comes when our rakish, mustachioed skipper, Jesus Lucio, tells us he grew up in Punta Alegre and has boated around Cayo Contrabandos most of his life.

Jesus drops both throttles and points the 40-foot Toro due north. We tool past the crowded beaches of Coco, the Parque Natural, and Guillermo and swing west into the deep blue waters off Isla Media Luna, finally taking in the seascape that beguiled both Hemingway and his fictional Hudson. Fifty miles to the southeast is Cayo Confites, where Fuentes babysat Hemingway's children when he wasn't captaining the Pilar; to the northwest is Cayo Frances, where Hudson communicated with a U.S. Navy outpost. Off the port bow, Jesus points out a boiler from a tanker sunk during WWII. Directly astern I see "the bight where [Hudson and his first mate, named Willie] had anchored and the beach and the scrub trees of Cayo Cruz that they both knew so well. . . . ."

After clandestinely trading a half bottle of rum to some fishermen for a hunk of fresh tuna, our best meal of the trip, Jesus points out Contrabandos. The tiny two-acre island hovers over the Caribbean like an emerald stepping stone. Mangroves crowd the western tip and a long coral point juts east toward Coco and Guillermo. I spot several sticks marking the sandbar on which Hudson runs aground in 'Islands'; Jesus avoids Hudson's fate by maneuvering along a deep channel leading to the island. There he rafts up with a fishing boat, the same model used by the "lobster police," in the lee of the key.

Jesus and a grizzled old fisherman paddle us in. Antonin and I break through the mangroves and find two abandoned foundations in a small clearing. Then I follow the gray coral shore around to the opposite side of the island. I'm not sure what I'm searching for: a shell casing, an ammo box, something to shed light on Hemingway's last great war story and the connection between him and Hudson.

Near a small spring I find a half-buried trash pile with antique glass fragments in it. One appears to be the top of a liquor bottle, another is embossed with the word "Dietz," a German name. I put both in my pocket and make my way back to the dinghy. We cast off and Jesus fires up the engines. The trip is over; we've reached the final page. Even Antonin is subdued in reflection at the site of Papa's last stand.

What we've found, we aren't exactly sure. Which might be the point, because neither was Hemingway. His time in the Jardines – always seeking, never quite finding – was more about conjuring a story than anything else. For Hemingway the ensuing tale was both the greatest and most devastating of his life, and it was the one that outlived him. As it did Thomas Hudson, felled by machine-gun fire off the shores of Contrabandos in the last paragraph of the novel.

"He felt the ship gathering her speed and the lovely throb of her engines against his shoulder blades, which rested hard against the boards. He looked up and there was the sky that he had always loved and he looked across the great lagoon that he was quite sure, now, he would never paint and he eased his position a little to lessen the pain. The engines were around three thousand now, he thought, and they came through the deck and into him.

"‘I think I understand, Willie,' he said.

"‘Oh shit,' Willie said. ‘You never understand anybody who loves you.'"