Legend had it that the doctor eventually began seeing the same ghosts his patients had reported and went insane. One night he climbed up the bell tower and jumped to his death. The remaining patients returned the doctor’s body to the bell tower and sealed the exits, entombing him forever. Shortly thereafter the hospital and the island were abandoned, but to this day Venetians reported hearing Poveglia’s bell ringing or seeing ghostly lights moving in the windows of the hospital wing.

Poveglia was, Maria told them, the most haunted place in Italy.

“No, I don’t buy the part about the ghosts,” Remi said, “but what went on in that hospital is well documented. Besides, the island’s closed to tourism. We’re breaking and entering.”

“That’s never stopped us before.”

“Just trying to be the voice of reason.”

“Well, I have to admit it’s very creepy, but we’re so close to solving this riddle I want to get it done.”

“Me, too. But promise me something: One gong from that bell tower and we’re gone.”

“If that happens you’ll have to race me to the boat.”

A few minutes later the mouth of the canal came into view. A few hundred yards down the shoreline they could see the dark outline of the hospital wing and bell tower rising over the treetops.

“See any phantom lights?” Sam asked.

“Keep joking, funny man.”

He maneuvered the dory through the chop created by the lapping waves and they slipped into the canal. Sheltered from the seaward side, the canal saw little circulation; the surface was brackish and dotted with lily pads and in some places the water was only a few feet deep. To their right a brick wall draped in vines slipped past; to their left, trees and scrub brush. Above they heard the rasp of wings and looked up to see bats wheeling and diving after insects.

“Just great,” Remi muttered. “It had to be bats.”

Sam chuckled. Remi had no fear of spiders or snakes or bugs, but she loathed bats, calling them “rats with wings and tiny human hands.”

Ten minutes later they reached the sandbar. Sam revved the engine, driving the bow onto the soil, then Remi got out and dragged the dory a few feet higher. Sam joined her and staked down the bow line. They clicked on their flashlights.

“Which way?” she asked.

He pointed to their left. “North end of the island.”

They walked across the sandbar, then up the opposite bank to a dense hedge of scrub. They found a thin spot, pushed their way through, and emerged in a football-sized field surrounded by low trees.

Remi whispered, “Is this . . . ?”

“It might be.” None of the maps of Poveglia had agreed upon the exact locations of the plague pits. “Either way, it’s odd that nothing’s growing here.”

They continued across the field, stepping gingerly and shining their flashlights over the dirt. If this was the site of a plague pit, they were treading on the remains of tens of thousands of people.

When they reached the opposite tree line Sam led them east for a hundred feet before turning north again. The trees thinned out and they emerged into a small clearing filled with knee-high grass. Through the trees on the other side of the clearing they could see moonlight glinting off water. In the distance rang a gong.

“Buoy in the lagoon,” Sam whispered.

“Thank God. My heart skipped a couple beats.”

“Here’s something.” They walked forward and stopped before a block of stone peeking above the grass. “Must have been part of a foundation.”

“Over there, Sam.” Remi was shining her flashlight at what looked like a fence post on the right side of the clearing. They walked over. Affixed to the post was a Plexiglas-enclosed placard:

Ninth-century site of the followers of Pietro Tradonico, Doge of

Venice 836 to 864. Remains disinterred and relocated in 1805.

—Poveglia Historical Society

“If Tradonico was here, he’s gone now,” Remi said.

“ ‘Relocated in 1805,’ ” Sam read again. “That was about the time Napoleon was crowned king of Italy, right?”

Remi caught on: “And about the time he had Poveglia converted to a munitions depot. If Laurent was with him, this is probably where they got their inspiration for the riddle.”

“And they would have known where Tradonico’s remains were sent. Remi, there was never a bottle here. The whole riddle was just a stepping-stone to send Napoleon Junior somewhere else.”

“But where?”

The next morning at two minutes after eight Sam and Remi’s water taxi stopped on a small side street two blocks east of Santa Maria Maddalena Church. They paid the driver, got out, and stepped up to a red door bordered by black wrought-iron railing. A tiny bronze plaque on the wall beside the door read, POVEGLIA HISTORICAL SOCIETY.

Sam pressed the buzzer. They heard footsteps clicking on wood and then the door opened, revealing a plump woman in a pink and yellow floral dress. “Sì?”

“Buon giorno,” Remi said. “Parla inglese?”

“Yes, I speak English very well. Can I help you?”

“Are you the curator?”

“Pardon?”

“Of the Poveglia Historical Society,” Sam said, smiling and pointing to the plaque.

The woman leaned out the door, squinted at the plaque, then frowned. “That’s old,” she said. “The society hasn’t met for five or six years.”

“Why?”

“All that ghost business. All people wanted to know about was the hospital and the plague pits. The rest of its history was forgotten. I was the secretary. Rosella Bernardi.”

“Perhaps you might be able to help us,” Remi said. She introduced herself and Sam. “We have a few questions about Poveglia.”

Signora Bernardi shrugged, motioned them inside, then led them down the hall into a kitchen decorated in black and white checkered tile. “Sit. I have coffee made,” she said, pointing to the kitchen table. She filled three mugs from a silver percolator then sat down. “What do you want to know?”

“We’re interested in Pietro Tradonico,” Sam said. “Do you know if he was buried on Poveglia?”

Signora Bernardi got up, walked across the kitchen, and opened a cabinet above the sink. She pulled down what looked like a brown leather photo album and returned to the table. She opened the album and flipped to a page near the middle. Under a sheet of acetate was a yellowed sheet of paper bearing dozens of lines of handwritten notes.

“Is that an original reference?” Remi asked.

“Sì. This is the 1805 government census data of Poveglia. When Napoleon ordered the island annexed the government hurried to erase its checkered past.”

“Which included the settlements established by Tradonico and his followers?”

“Yes, those, too. According to this, Pietro Tradonico and his wife, Majella, were buried side by side on Poveglia. When they were disinterred, their bones were stored together in the same coffin then temporarily placed in the basement of the Basilica della Salute.”

Sam and Remi exchanged a glance. Here was the solution to the riddle’s last line, Together they rest.

“You said temporarily,” Sam said. “Does it say where the remains went after that?”

Signora Bernardi traced her index finger down the sheet, then flipped to the next page; halfway down the next sheet she stopped. “They were taken home,” she announced.

“Home? Where exactly?”

“Tradonico was Istrian by birth.”

“Yes, we know.”

“Members of the Tradonico clan came and took the bodies to their village of Oprtalj. That’s in Croatia, you know.”

Remi smiled. “Yes.”

“What they did with Tradonico and his wife once they reached Peroj we don’t know. Does that answer your questions?”

“It does,” Sam said, then stood up. Both he and Remi shook Signora Bernardi’s hand, then walked down the hall and out the front door, where she stopped them. “If you find them, please let me know. I can update my records. I doubt anyone else will ask, but at least I’ll have it written down.”