High in the hayloft at Château Villette, Collet stared at the computer monitor in amazement. "This system is eavesdropping on all these locations?"

"Yes," the agent said. "It looks like data has been collected for over a year now."

Collet read the list again, speechless.

COLBERT SOSTAQUE—Chairman of the Conseil Constitutionnel

JEAN CHAFFÉE—Curator, Musée du Jeu de Paume

EDOUARD DESROCHERS—Senior Archivist, Mitterrand Library

JACQUES SAUNIÈRE—Curator, Musée du Louvre

MICHEL BRETON—Head of DAS (French Intelligence)

The agent pointed to the screen. "Number four is of obvious concern."

Collet nodded blankly. He had noticed it immediately. Jacques Saunière was being bugged. He looked at the rest of the list again. How could anyone possibly manage to bug these prominent people? "Have you heard any of the audio files?"

"A few. Here's one of the most recent." The agent clicked a few computer keys. The speakers crackled to life. "Capitaine, un agent du Département de Cryptographie est arrivé."

Collet could not believe his ears. "That's me! That's my voice!" He recalled sitting at Saunière's desk and radioing Fache in the Grand Gallery to alert him of Sophie Neveu's arrival.

The agent nodded. "A lot of our Louvre investigation tonight would have been audible if someone had been interested."

"Have you sent anyone in to sweep for the bug?"

"No need. I know exactly where it is." The agent went to a pile of old notes and blueprints on the worktable. He selected a page and handed it to Collet. "Look familiar?"

Collet was amazed. He was holding a photocopy of an ancient schematic diagram, which depicted a rudimentary machine. He was unable to read the handwritten Italian labels, and yet he knew what he was looking at. A model for a fully articulated medieval French knight.

The knight sitting on Saunière's desk!

Collet's eyes moved to the margins, where someone had scribbled notes on the photocopy in red felt-tipped marker. The notes were in French and appeared to be ideas outlining how best to insert a listening device into the knight.