Radford, Garza thought. Luckily, the idiot woman had had no inkling of the significance of what she’d found, treating it as nothing more than a trinket, showing it off around Zanzibar and Bagamoyo, asking locals what it might be. The necessity of her death had been unfortunate, but Rivera had handled it with his usual care-a street robbery turned murder, the police had concluded.

What Ms. Radford actually found had been the thinnest of threads, one that would’ve required careful and expert teasing lest it snap. But the Fargos . . . They knew all about following random threads, he suspected. The Fargos knew how to uncover something from nothing.

“Could she have told someone what she found?” Garza asked. “The Fargos have their own intelligence network of sorts, I would imagine. Could they have gotten a whiff of something?” Garza narrowed his eyes and stared hard at Rivera. “Tell me, Itzli, did you miss something?”The gaze that had withered many a cabinet secretary and political opponent left Rivera unfazed; the man merely shrugged.

“I doubt it, but it is possible,” he said calmly.

Garza nodded. Though the possibility of Ms. Radford having shared her find with someone was disconcerting, Garza was pleased Rivera had no trouble admitting he may have made a mistake. As president, Garza was surrounded daily by sycophants and yes-men. He trusted Rivera to give him the unvarnished truth and to fix the unfix-able, and he’d never failed in either respect.“Find out,” Garza ordered. “Go to Zanzibar and find out what the Fargos are up to.”

“And if this isn’t a coincidence? They wouldn’t be as easy to handle as the British woman.”

“I’m sure you’ll work it out,” Garza said. “If history has shown us anything, it’s that Zanzibar can be a dangerous place.”

ZANZIBAR

AFTER TALKING WITH SELMA, SAM AND REMI TOOK A CATNAP, then showered, changed clothes, and took their scooters down the coast road to Stone Town, to their favorite Tanzanian cuisine restaurant, the Ekundu Kifaru-Swahili for “Red Rhino.” Overlooking the waterfront, the Red Rhino was nestled between the Old Customs House and the Big Tree, a giant old fig that served as a daily hangout for small boat builders and charter captains offering day sails to Prison Island or Bawe Island.

For Sam and Remi, Zanzibar (or Unguja in Swahili) personified Old World Africa. The island had over the centuries been ruled by warlords and sultans, slave traders and pirates; it had been the head-quarters for trading companies and the staging area for thousands of European missionaries, explorers, and big game hunters. Sir Richard Burton and John Hanning Speke had used Zanzibar as the base for their search for the source of the Nile; Henry Morton Stanley had begun his famous hunt for the wayward David Livingstone in the labyrinthine alleys of Stone Town; Captain William Kidd had reputedly sailed the waters around Zanzibar as both pirate and pirate hunter.Here, Sam and Remi found every street and courtyard had a story and every structure a secret history. They never left Zanzibar without dozens of fond memories.

By the time they pulled into the parking lot the sun was dropping quickly toward the horizon, casting the sea in shades of gold and red. The scent of oysters on the grill drifted in the air.“Welcome back, Mr. and Mrs. Fargo,” the valet called, then signaled for a pair of white-coated attendants, who trotted over and pushed the scooters away.

“Evening, Abasi,” Sam replied, shaking the valet’s hand. Remi received a warm hug. They’d met Abasi Sibale on their first visit to Zanzibar six years earlier and had become fast friends, usually having dinner with him and his family at least once during their yearly visits. Abasi was never without a smile.“How’re Faraja and the kids?” Sam asked.

“Happy and healthy, thank you. You will come to supper while you are here?”

Remi smiled. “Wouldn’t miss it.”

“I believe they are ready for you inside,” Abasi said.

Just inside the door the maitre d’, Elimu, was waiting. He, too, had known the Fargos for years. “Good to see you, good to see you. Your favorite table overlooking the harbor is ready.”

“Thank you,” Sam said.

Elimu led them to a corner table lit by a red hurricane lantern and surrounded on two sides by open windows overlooking the waterfront. Below, Stone Town’s streetlights were flickering to life.“Wine, yes?” Elimu asked. “You would like the list?”

“Do you still have that Pinot Noir-the Chamonix?”

“Yes, we have a ’98 or a 2000.”

Sam looked to Remi, who said, “I still remember the ’98.”

“As the lady wishes, Elimu.”

“Very good, sir.”

Elimu disappeared.

“It’s beautiful,” Remi murmured, staring out over the ocean.

“I couldn’t agree more.”

She turned her head away from the window, gave him a smile, and squeezed his hand. “You got a little sun,” she remarked. For some inexplicable reason, Sam Fargo burned oddly-today, only the bridge of his nose and the tips of his ears were pink. Tomorrow they would be bronze. “You’re going to be itchy later.”“I’m itchy now.”

“So, any guesses?” Remi asked, holding up the diamond coin.

It had spent the afternoon first sitting in a bowl of ten percent nitric acid, followed by Sam’s secret formula of white vinegar, salt, and distilled water, followed by a scrubbing with a soft-bristle toothbrush. While many spots remained obscured, they could make out a woman’s face in profile and two words: “Marie” and “Reunion.” These details they’d relayed to Selma before leaving the bungalow.“Not a one,” Sam said. “An odd shape for a coin, though.”

“Private minting, perhaps?” “Could be. If so, it’s well done. Nice clean edges, good tooling, solid weight . . .”

Elimu returned with the wine, decanted, poured for both of them, waited for their nods of approval, then filled their glasses. This particular Pinot Noir was South African, a rich red with hints of cloves, cinnamon, nutmeg, and something Sam couldn’t quite place.Remi took a second sip and said, “Chicory.”

Sam’s phone rang. He looked at the screen, mouthed, Selma , then answered. “Evening, Selma.” Remi leaned forward to listen in.

“Morning for me. Pete and Wendy just got here. They’re starting on the Tanzanian law angle.”

“Perfect.”

“Let me guess: You’re sitting at the the Ekundu Kifaru, staring at the sunset.”

“Creatures of habit,” Remi said.

“You have news?” Sam asked.

“About your coin. You have yourself another mystery.”

Sam saw the waiter approaching and said, “Hold a minute.” They ordered a Samakai wa kusonga and wali-fish croquet and native rice with chapati bread-and for dessert, N’dizi no kastad-Zanzibar-style banana custard. The waiter left, and Sam un-muted Selma.“Go ahead, Selma. We’re all ears,” Sam said.

“The coin was minted sometime in the early 1690s. Only fifty were made, and they never saw official circulation. In fact, they were a token of affection, for lack of a better term. The ‘Marie’ on the coin’s face is part of ‘Sainte Marie,’ the name of a French commune situated on the north coast of Reunion Island.”“Never heard of it,” Remi said.

“Not surprising. It’s a little lump of an island about four hundred miles east of Madagascar.”

“Who’s the woman?” Sam asked. “Adelise Molyneux. The wife of Demont Molyneux, the administrator of Sainte Marie from 1685 to 1701. According to the stories, for their tenth anniversary Demont had his private stock of gold melted down and minted into these Adelise coins.”“Quite a gesture,” Remi said.

“The coins were supposed to represent the number of years Demont hoped they would spend together before dying. They came close. They both died within a year of each other, just shy of their fortieth anniversary.”“So how did this one get all the way to Zanzibar?” Sam asked.