When Jay Miscovich stepped off Duval Street into the Bull & Whistle bar in January 2010, Key West was shivering through a cold spell, the thermometer parked at a rare 70 degrees. A bearish guy in his 50s with a beach-ball gut and an ever-present baseball cap pulled over his bald head, he crossed the stone floor, extending a hand to an old acquaintance.

The room was nearly empty. Afternoon shadows mossed the high ceilings. Steer horns poked from the corners. The walls surrounding the U-shaped bar were splashed with fading murals of Florida legends, yellowed like old photos: a beer-bloated Hemingway; railroad baron Henry Flagler; and next to a pair of regal galleons, Mel Fisher, the famous treasure hunter.

Even though Miscovich hadn't seen him in over a decade, Mike Cunningham looked the same. A drifter, he was tanned and whittled thin from day labor. A clean white sweatshirt hung off his shoulders.

"How's it going?" Miscovich asked, his consonants sloshing around in a wet lisp. When he'd known Cunningham years earlier, back in their hometown of Latrobe, the handyman had been painfully shy, preferring to mow grass or paint walls alone. Back then, Miscovich hired him regularly, and Cunningham still checked in a few times a year after moving to Florida for year-round work. Knowing that his former employer had an interest in treasure hunting, he'd asked to meet today.

Cunningham pulled out a worn plastic bag holding a brown piece of pottery. From the cracked glaze, Miscovich guessed the piece could be Spanish colonial — valuable.

Cunningham next unfolded a piece of paper — a photocopy of a nautical chart. No GPS coordinates. Handwritten on the paper was an X, the words "pirate wreck," and rough drawings of cannon. Cunningham explained he'd found the pottery while diving in the Gulf of Mexico with friends.

"Do you think you'd give me $500 for it?" Cunningham asked. The pottery alone sold Miscovich. But the chart also lit his interest. If there were more pottery at the site, $500 wouldn't be a bad investment.

After the money changed hands, Cunningham left. Miscovich drank two more beers alone, silently toasting the possibilities.

It wasn't until Miscovich was on the stand in a federal trial that he publicly served up this story — of how he, a broke no-name from Pennsylvania, had stumbled into a potential multimillion-dollar treasure find. By then — almost three years after hitting the jackpot — he was probably Key West's most hated figure.

To Conchs, it was unbelievable that this stranger could have lucked into a jackpot that had eluded hundreds of other divers for decades. Key West's treasure-hunting community smelled a fraud, and Miscovich's far-fetched tale about treasure maps in bars seemed proof-positive.

But it was undeniable that Miscovich now had bags and bags of little green rocks. Were they really priceless or just costume junk barely worth their weight in rhinestones? And most mysteriously of all, where had they come from?

One entity would be particularly interested in digging up the truth: the world's most powerful treasure-hunting family.

Black or shiny. The two words were on replay in Steve Elchlepp's mind as he breathed through his regulator and scanned the bottom of the Gulf of Mexico about an hour's boat ride from Key West. Black or shiny.

Through the shifting water, the muscular dive instructor could make out Miscovich, wrapped in a black wetsuit, waving a metal detector over the sand. Here, 50 feet below the surface, mixed-up currents created fun-house tricks of perspective, the visibility collapsing and expanding and collapsing again. Blankets of blues and grays billowed like laundry on a clothesline in a windstorm. Black or shiny.

To stay oriented, Elchlepp kept his eye on the floor, on alert for silver (which, after hundreds of years in salt water, turns black from oxidation) or gold (which never loses its shine). Black or shiny.

Fifteen feet away, Miscovich was waiting for a ping from the metal detector patched into his mask. After following the map's lead, the pair had scanned the ocean floor for two days with a sensor dragging behind their boat but hadn't picked up any signals. Today, day three, they expanded their scan area, finally picking up traces of metal. But each trip below yielded nothing. Miscovich was getting frustrated. So far, all he had found were some Bud Light cans, and this was their last dive of the afternoon.

Like any experienced diver, Elchlepp periodically checked on his friend. On one of those glances, he saw Miscovich jabbing his finger toward the surface, signaling his partner topside. He'd found something.

Bobbing near the anchored boat, Miscovich showed what was cupped in his hand: quarter-sized chips of green rocks.

"I think those are frickin' emeralds," Miscovich told his partner. "Steve, there's thousands of them down there."