“ ‘It is written in Raz Sodekhah,’ ” read the old man, “ ‘that Lord Dantalion is none other than the serpent who tempted Adam and Eve in the Garden of Eden, but this is commonly held to be poetic metaphor. The Daas HaGanuz, however, brings a rumor that there was a discrepancy in punctuation between the original Ten Commandments destroyed by Moses at the foot of Mount Sinai and the replacements issued by the Holy One, Blessed Be He. The Daas HaGanuz contends that it is this discrepancy, known only by Moses, that is the beginning of the Dantalion….’ ”

Yehuda Leib turned back to find Mammon grinning ear to ear. “One could study here forever,” he said, “and still not come any closer to the secret one seeks.”

“But there must be a way forward,” said Yehuda Leib.

“Oh,” said Mammon, turning them toward a narrow gap between two bookcases. “There is. If one is wise enough to discern the shape of truth beneath the outer layers of rumor and misunderstanding…”

A spindly, steep staircase plunged down into the darkness between the bookcases, one single point of jumping candlelight dancing at its bottom.

“But one may only move forward,” said Mammon, clambering downward into the darkness, “if one passes the examination.”

—

The man who sat squinting at his reading beside the candle at the bottom of the stairs was impossibly old. He had fewer teeth remaining than he had eyes, and his beard seemed to be at least half cobwebbing.

“You wish to pass into the second chamber?” he said in a rasping voice.

“Yes,” said Yehuda Leib.

“Very well,” said the man, sitting up officiously. “Tell me a secret.”

Yehuda Leib’s heart began to thunder.

Tell me a secret? This seemed like an impossible examination to pass. Was he supposed to tell a specific secret? Or perhaps one that the man had never before heard? What secret could he possibly possess that would be good enough to merit entrance?

But Mammon simply smiled and shouldered past Yehuda Leib.

“No,” said the little demon.

No?

“Correct,” said the man at the candle, reaching up to draw back a door hidden in the gloom.

“No?” said Yehuda Leib. “How can the correct answer be no?”

“Nothing one learns in Dantalion’s yeshiva is of any consequence whatsoever,” said Mammon. “It is a suit of armor in the shape of an academy. But some benefit can still be gained from studying here—not in information, of course, but in the knowledge of how to discern the truth hidden beneath it. If you were to tell the first door guard a secret as he requested—any secret at all—then you would be divulging it. This would render it no longer secret, which, in turn, would invalidate your answer. Therefore, the only satisfactory response is no.”