That made sense because in the diagrams, the excavation under Brumaire met up eventually with another system of caverns dug under the woods. If this was correct, then Gilles and Daniel had bored out another thirty or forty yards to link up with a big cavern situated beneath the north-east corner of the garden.

I followed the corridor until it opened to an empty blackness. I located the light switch on the inside to the left. I flicked it on and the magnificent vault ceiling was revealed by a dozen strategically placed spots and floods, casting warm light over the white stone ceiling, cross-hatched and scored by mattock blows. Vaugeois had set anchors into the stone every couple of yards to reinforce the structure. This was set up for festive occasions. On one side of the room were folding tables covered in plastic tarps, stacked close to the wall. The air was cool and humid, and smelled musty.

On the other side I spotted a dark tunnel entrance. From the maps I knew that this was the part of the excavation that would eventually lead up to the forest mound entrance. It hadn’t been cleaned up. The old tunnel went on for fifteen unlit yards. Over to my right was yet another dark entrance, bigger, and darker. According to Gilles’ maps this one went further and longer. It ran along the river bank and ended at some point. The excavation looked rougher, older and less maintained. I walked through it for a while, but it wasn’t long before there was nothing to see, no lights, just pure black darkness.

I retraced my steps and returned to the house, switching off the lights and closing and locking the door behind me. It was warmer up top, the kitchen smells wafted around and I was drawn to it, like a bat to flies.

We didn’t speak much at dinner, just ate and drank and made small talk. Simone occupied herself with the logistics of it, with Nazari and me helping whenever something needed to be carried. I didn’t want to discuss the evening’s plans in front of the madame and she seemed to realize that. She went pretty heavy on the red wine and I figured she was dosing herself for an early night.

When we had finished eating, Nazari and I excused ourselves and thanked Simone for dinner.

“You didn’t eat much cheese.”

“I wasn’t terribly hungry, ma’am, I promise to eat more cheese tomorrow.”

Nazari went to the bathroom and I walked around to the other side of the house and entered Gilles’ library. I flicked on the light and closed the door. Then went around the big desk and pulled open the drawer. The mini-mag light was there waiting. Exactly where it had been before. The batteries had juice. I pocketed the heavy steel thing.