Anyone who spends even a modicum of time chasing shipwrecks finds themselves well versed in every facet of a vessel’s history. That Rivera feigned ignorance about the Ophelia told Sam and Remi that the ship was vitally important to Rivera and his employer.“Did he mention the hidden engraving?”

“No. That could be telling. It’s another thing an experienced hunter would know. He didn’t mention it because he’s hoping we missed it.”

“Any hint as to what specifically they’re after?” “He implied it was something in the Ophelia’s hold. Treasure of some kind. Even offered us a finder’s fee.”“How very kind of him. Where does this leave us?”

“Rivera claimed he had salvage experience, which may or may not be true, but he also claimed his patrons have been actively looking for the Ophelia.”

In the world of treasure hunting, an active search is a specific beast that involves mounting expeditions-getting wet and dirty while laying out grids, doing magnetometer passes, picking through muck and slime. Not to mention the dry but no less daunting research work: interviewing relatives, scouting locations, and sitting in dusty old libraries looking for the slightest clue as to the target’s possible location.“If Rivera’s been at it that long,” Remi said, “there’ll be public records, news stories, permits . . .”

“My thought exactly. We find those, we get a better idea of what Rivera and his people are really after.”

THEY SAT UNDER the shade trees outside the police station for ten minutes as Sam watched Rivera and his partner leave the cricket grounds parking lot, then overtly make a circuit around the police station. Sam and Remi gave them a parting wave on the last pass.

Once sure they weren’t returning, Sam and Remi walked east to an open-air market, where they gathered food and necessities and walked the labyrinthine alleys while watching for signs of pursuit. Finding none, they walked three blocks north to a rental-car agency. Their reservation, a 2007 Toyota Land Cruiser, was waiting for them. Forty minutes later they were back at their Uroa beach villa.Sam’s phone trilled as they were walking up the driveway. Remi gestured for the bag of groceries he was carrying and continued into the villa. Sam checked the caller ID: Rube.

“Morning, Rube.”

“Early, early morning. How did your meeting go?”

“Fine. Huru told us to say hello.”

“A good man, Huru. Did you turn your guest over to him?” “Not yet,” Sam replied, then recounted his conversation with Rivera. “We already called Selma. She’s working on shipwreck databases for the area. Tomorrow we’re going over to the university for a little homework.”

“Well, I know I already said this once, but be damned careful. I did some digging into Itzli Rivera. The military stuff you already know, but he was also in their defense department’s intelligence section. He retired about eight years ago and went private. Here’s the kicker: According to the chief of station in Mexico City, Rivera’s been arrested six times by the Policia Federal but never indicted.”“What charges?”

“Burglary, bribery, blackmail, murder, kidnapping . . . And all related to national-level politics.”

“So he’s a hatchet man.”

“A militarily trained hatchet man. It’s a distinction to keep in mind. Nobody can pin down who he works for.”

“How’d he beat all the charges?”

“The usual: witness recantation either by change of mind or change in corporeal status, as in sudden and unexpected death.”

Sam chuckled. “Yes, Rube, I get it.”

“The rest is pretty standard stuff: mislaid evidence, technicalities, etcetera.”

“Safe to say Rivera’s got a heavyweight in his corner.”

“A heavyweight with a fetish for shipwreck artifacts. What’re you going to do with the bell?”

“We haven’t decided yet. The truth is, I don’t think they really care about the bell itself. Whether they’re after the Ophelia or the ship belonging to the mystery engraving, it doesn’t change where we found the thing. That’s what’s got them worried . . . Well, that and the fact that we aren’t willing to leave it alone.”“Maybe it’s not about something they’re looking for,” Rube said, “but rather something they don’t want anyone else to find.”

“Interesting,” Sam said.

Rube continued: “That charitable donation business . . . He wanted you and Remi and the bell together in one place. Why not just accept an e-mailed picture of the bell? And if all they wanted was to find the Ophelia, why not hire you? Everyone knows how the Fargos work: A large percentage of the find goes to charity and nothing to you personally. Sam, I think this is about hiding something, not finding something.”

UNIVERSITY OF DAR ES SALAAM

THE UNIVERSITY’S CENTRAL CAMPUS SAT NORTHWEST OF THE CITY center on a hill. Having called ahead, Sam and Remi found the library’s director, Amidah Kilembe, a beautiful black woman in a fern-green pantsuit, waiting to greet them on the steps.“Good morning, Mr. and Mrs. Fargo. Welcome to our facility.”

Pleasantries were exchanged as Ms. Kilembe took them up the steps and through the main doors, at which point she gave them a walking tour of the building, which eventually took them to the third-floor reference area. The decor was a mixture of Old World colonial and traditional African: dark furniture and paneling that glowed from decades of polishing surrounded by splashes of colorful Tanzanian art and artifacts. Save a few of the library staff, the building was empty. “It’s a school holiday,” Ms. Kilembe explained.“We’re sorry,” Sam said. “We thought-”

“Oh, no, no. For the staff it is a regular workday. In fact, as chance would have it, you’ve chosen the perfect day to visit. I myself will be assisting you.”

“We don’t want to impose,” Remi said. “I’m sure you have other . . .”

Ms. Kilembe smiled broadly. “Not at all. I have read of, and enjoyed, several of your exploits. I will, of course, keep my silence about what we discuss here today.” She touched an index finger to her lips and winked. “If you’ll follow me, I have a quiet room set aside for you.”

They followed her to a glass-enclosed room, in the center of which sat a long walnut table and two padded chairs. Before each chair sat a twenty-inch Apple iMac computer. Ms. Kilembe saw their surprised expressions and chuckled. “Three years ago Mr. Steve Jobs himself visited the campus. He saw that we had very few computers and all of them old, so he made a generous donation. We now have forty of these wonderful machines. And broadband Internet!

“Very well. I will let you get started. First, I will bring you coffee. I have you both set up with guest log-ins for the catalogues. Most of our materials have been digitized back to 1970. Those that have not been will be in our basement archives area. You tell me what you need, and I will bring it. So, good hunting!”And then Ms. Kilembe was gone, pulling the door shut behind her.

“Where do we start?” Sam wondered aloud.

“Let’s check in with Selma.”

Sam double-clicked the iChat icon on the screen and typed in Selma’s address. The computer’s iSight camera turned green and in ten seconds Selma’s face appeared on the screen.“Where are you?” she asked.

“University of Dar es Salaam.”

Behind Selma, Pete and Wendy were sitting at the worktable. They waved.

Remi said, “We’re getting ready to dig in. Do you have anything for us?”

“The last search is finishing now.”

On-screen, Pete walked across to a computer workstation, tapped the keyboard a couple times, then called, “Coming over to you, Selma.” Sam and Remi watched as Selma studied the document, her eyes darting across the screen.

At last she said, “Not much there. We checked all the major shipwreck databases and found only eighteen sites in the waters around Zanzibar. We even extended the grid fifty miles on all compass points. Of the eighteen, fourteen are identified, and only one of those comes even remotely close to the assumed same time frame as the Ophelia .”“Go on.”