Rustam turned the page.

"David said he was the last keeper of an ancient secret. His teacher, a European monk named Thomas, had entrusted him with preserving knowledge about a Nestorian treasure hidden during the Mongol invasion. Among the treasures was a special item that David called the 'Key of Solomon'—a crystal with extraordinary properties."

"A crystal?" Alexei asked. "Not the medallion?"

"The medallion is a pointer, a guide to the crystal," Rustam explained. "The real 'Key of Solomon' is a crystal hidden in a cache." He continued translating: "David was too old to keep the secret himself. He gave my ancestor a map indicating the place where the treasures were hidden and said that someday a person would come who could find and use the 'Key of Solomon' for good. Until then, the secret must remain hidden."

"And where is this map now?" asked Alexei.

"Lost," Rustam replied regretfully. "During the civil war, our house was burned down, and many family heirlooms disappeared. Only this diary remained, which my grandfather managed to hide." He closed the book. "But even without the map, I know where to look. Our ancestor passed this knowledge to his son, who passed it to his son, and so on from generation to generation. Thus the secret came down to my father, and my father passed it to me."

"And you never tried to find the treasures yourself?" asked Dinara.

"I tried, when I was young and hot-headed," Rustam smiled. "But my ancestor left a warning: without the medallion, finding the cache is impossible. And the medallion was lost in David's time." The old man looked at Alexei. "At least, that's what we thought until your grandfather found it in 1954."

"But why didn't my grandfather use the medallion to find the treasures?" Alexei wondered. "Why did he simply hide it and tell no one?"

"Because it was a dangerous time," Rustam answered. "The USSR, the Cold War, the KGB watching every step. Igor understood that if the authorities learned about the 'Key of Solomon,' they would do everything to get it. And if the legend is to be believed, this crystal possesses extraordinary power. In the hands of those who crave power, it could become a dangerous weapon."

"What kind of power exactly?" asked Alexei.

Rustam smiled mysteriously.

"They say the crystal can heal diseases, prolong life, and even open the 'eyes of the soul,' allowing one to see the true nature of people and things. But there is also a warning: it amplifies both the light and dark sides of human nature. In the hands of a good person, it works miracles. In the hands of an evil one—it brings calamity."

"Sounds like a myth," Alexei remarked.

"Perhaps," Rustam agreed. "But your grandfather, a scientist and skeptic, believed in this legend enough to keep the medallion secret all his life. That makes one think, doesn't it?"

Dinara looked at the medallion lying on the table.

"What about these symbols?" she asked, pointing to the strange marks on the reverse side of the medallion. "What do they mean?"

"It's a combination of Nestorian script and special symbols known only to initiates," Rustam replied. "A kind of cipher. But I cannot read it completely. My father couldn't either. That part of the knowledge was lost."

"And the inscription inside?" asked Alexei. "'Lux in aqua, aqua in luce. Clavis Salomonis aperiet viam.' Light in water, water in light. Solomon's key will open the way."

"That's a clue," said Rustam. "Light in water, water in light' is a description of a special phenomenon that can be observed only at a certain time of year and in a specific place on Issyk-Kul. When the sun rises and its first rays penetrate the water at a particular angle, creating the illusion that the lake is glowing from within. And at that moment, an entrance to a cave, hidden at other times, becomes visible."