“We understand,” Sam replied.

“The story goes that De Terzi could find no investors for his aircraft plan.”

“The Vacuum Ship.”

“Yes, that. He could find no one to give him money, not the government, not wealthy men here. He journeyed east hoping to find support so he might finish his work.”

“And did he?”

“No, not that I am aware of.”

“What happened when he returned in 1679?” Sam said.

“It is said he returned to Italy a changed man. Something bad had occurred during his travels, and Giuseppe did not return home. Francesco never spoke of that. Soon after, he resettled in Brescia, left the Jesuit Order, and moved to Vienna, Austria.”

“In search of investors again?”

“Perhaps, but in Vienna he found only bad luck.”

“How so?” asked Remi.

“Soon after he moved to Vienna he married, and then quickly followed a baby boy. Two years later came the big battle-the Siege and then the Battle of Vienna. Do you know of it?”

“Only vaguely.”

“The Siege lasted for two months, the Ottoman Empire fighting the Holy League: the Holy Roman Empire, the Polish-Lithuanian Commonwealth, and the Venetian Republic. In early September of 1683, the final battle was fought. Many tens of thousands of people died, including Francesco De Terzi’s wife and new son.”

“That’s awful,” Remi said. “So sad.”

“Si. It is said he was terribly heartbroken. First his brother, and then his new family, all dead. Shortly afterward, De Terzi disappeared again.”

“Where?”

Moretti shrugged. “Again, a mystery. He returned again to Brescia in October of 1685, and then died a few months later.”

“Let me ask you what may sound like an odd question,” Remi said.

“Please.”

“Are you, or anyone, absolutely certain De Terzi returned to Brecia in 1685?”

“That is an odd question. I suppose the answer would be no. I know of nothing that certifies he was buried here-or that he returned, for that matter. That part of the story is, like the rest, based on secondhand information. Short of an . . .”

“Exhumation.”

“Yes, an exhumation. Only that, and a DNA sample from his descendants, would be proof. Why do you ask? Do you have reason to believe-”

“No, not really. We’re brainstorming.”

Sam asked, “About these stories: do you believe any of them?”

“Part of me wants to believe. It is a thrilling adventure, yes? But, as I said, the official histories of De Terzi’s life contain none of these accounts.”

“A few minutes ago you said there is so little documentation. Does that mean there is some documentation?” Remi said.

“There are a few letters, but written by friends. None in De Terzi’s own hand. It is what your justice system calls hearsay, si? Aside from those, there is only one other source that may be related to the stories. I am reluctant to mention it.”

“Why?”

“It is fiction, a short story written by De Terzi’s sister a few years after his death. Though named differently, the protagonist is clearly intended to be Francesco. Most thought the sister was trying to make money on his fame by exploiting the rumors.”

“Can you give us the gist of the story?”

“A fanciful tale, really.” Moretti gathered her thoughts. “The hero of the story leaves his home in Italy. After braving many dangers, he is captured by a tyrant in a strange land. He is forced to build a flying ship of war. The ship crashes in a desolate place, and just the hero and two of his comrades survive, only to eventually die of their injuries. The hero then finds a mysterious treasure, which the natives tell him is cursed, but he ignores the warning and undertakes an arduous journey back to the tyrant’s castle. Once there, he finds that his traveling companion, who the tyrant had been holding hostage, has been executed.

“The hero returns to Italy with the treasure only to find more tragedy: his family has been killed by the plague. The hero is now convinced the curse is real, so he sets out to return the treasure to where he found it and is never heard from again.”

Sam and Remi struggled to keep their faces expressionless.

Sam said, “You don’t happen to have a copy of this story, do you?”

“Yes, of course. I believe I have it in the original Italian as well as a very good English translation. As soon as we have finished our conversation, I will send you an electronic version.”

GOLDFISH POINT, LA JOLLA

CALIFORNIA

With copies of “The Great Dragon” on each of their iPads, Sam and Remi thanked Professor Moretti for her help. Sam and Remi read the story and e-mailed copies to Selma, Wendy, and Pete. As Remi was sending a copy of the story to Jack, Selma connected with him via iChat.

“You two look absolutely giddy,” Karna said. “Don’t keep me in suspense. What have you found?”

Sam said to Remi, “You tell him.”

Remi first recounted their conversation with Moretti, then gave everyone a summary of “The Great Dragon.”

“Incredible,” said Selma. “You’ve both read the story?”

“Yes,” said Sam. “It should be in your e-mail. You too, Jack.”

“Yes, I see it here.”

“How closely does the story match the bamboo engraving?” asked Wendy.

“If you replace the clearly fictional bits of the story with De Terzi’s alleged testament, you get what reads like a factual account: the crash, the number of survivors, the discovery of a mysterious treasure, the trek home . . . It’s all there.”

“And the time line fits,” Remi said. “Between the secondhand accounts of De Terzi’s comings and goings, he could easily have been traveling to and from China.”

“I am flabbergasted,” said Karna.

Pete, who was paging through the story on Sam’s iPad, said, “What’s this map on the frontispiece?”

“That’s the hero’s journey to return the treasure,” replied Remi. “Jack, do you have that?”

“Looking at it right now. It appears De Terzi arrives from the west and first stops at what is labeled here as a castle. This, we can assume, is Shekar Gompa.”

“The launch base for the airship,” Sam said.

“And possibly the burial site for Giuseppe,” added Remi.

Karna continued: “From Shekar Gompa, De Terzi travels east to the Great City. Based on the position of Shekar, the city could be Lhasa.”

“Why would he go there?” asked Wendy. “The crash site is forty miles south of Shekar Gompa. Wasn’t he trying to return the treasure?”

“Yes,” Sam replied, “but in the story when he reaches the castle a local wise man tells him he must return the treasure to ‘its rightful home.’ He is told to seek out another wise man in the Great City to the west.”

Karna picked up Sam’s line of thought: “From the Great City, De Terzi continues eastward, eventually arrives at . . . I don’t know. There’s only an X here.”

“Shangri-La,” Remi suggested.

There were a few moments of silence from Karna, then: “You’re going to have to excuse me. Apologies. I’ll get back to you.”

The iChat screen went dark.

Karna was back thirty minutes later. “There are some rough grid lines and other landmarks on this map I’ll have to cross-reference, but using the distance from Shekar Gompa to Lhasa as a benchmark, the final leg of De Terzi’s journey ended in an area that’s know today as the Tsangpo Gorge.”

“Your front-runner for the location of Shangri-La,” said Sam.

“Yes indeed. Sam, Remi, you may have just solved a riddle six hundred years in the making.”

Sam said, “Let’s not get ahead of ourselves. How long will it take you to nail down the locations on the map?”

“I’ll start right now. Give me a day.”

ARUNACHAL PRADESH REGION

NORTHERN INDIA

“Jack!” Remi called. “I didn’t really believe you’d show up.”