The screen flickered. A progress bar appeared: But the file size was impossibly small—just 2 KB.

Armand leaned forward. "Logiciel Sphinx... telecharger?"

When the download finished, they opened the file. Inside was a single line of characters: a string of numbers and letters that looked like a cryptographic key. And below it, a new instruction:

Years later, after they had excavated the chapel's foundation and discovered the lost royal seals of Aquitaine, Léa would smile whenever a student asked her about the "Sphinx software."

"Oh, that," she would say. "You can't download it. It downloads you."

"That's not a program," Armand grumbled. "That's a text file."

"Je parle sans bouche et j’entends sans oreilles. Je n’ai pas de corps, mais je viens à toi avec le vent. Que suis-je?"