He did. And Beauvoir turned it around so that it faced him.

The crisis was averted. He sat back down in his chair. The chronic ache had turned into a sharp pain that tunneled into Beauvoir’s bones and ran through his marrow. Like corridors, carrying the pain to every part of his body.

Beauvoir began wondering how soon he could be alone in the office. With the computer. And the DVD the Superintendent had brought. And the pills the doctor had left. He now longed for the next service. So that while everyone else was in the Blessed Chapel he could be in here.

They spent the next twenty minutes discussing the case, throwing around theories, throwing out theories, until finally Gamache got to his feet.

“I need a walk. Do you want to come?”

Beauvoir’s heart sank, but he nodded and followed Gamache into the corridor.

They turned toward the Blessed Chapel, when the Chief suddenly stopped and stared, at the electric light bulb attached to the wall.

“Do you know, Jean-Guy, when we first arrived I was surprised they had electricity here.”

“Comes from solar and some hydro power they’ve hooked up to a nearby river. Frère Raymond told me. Want to know how it works? He told me that as well.”

“Perhaps for my birthday. As a special gift,” said the Chief. “But what I’m wondering now is how that light got there.”

He pointed to the wall sconce.

“I don’t understand, patron. How does any light get on a wall? It’s wired there.”

“Exactly. But where’re the wires? And where’s the ductwork for the new heating system? And the pipes for the plumbing?”

“Where they are in any building,” said Beauvoir, wondering if the Chief had lost his mind. “Behind the wall.”

“But the plan shows only one wall. The Gilbertines who built it took years, decades, to dig the foundation and put the walls up. It’s an engineering marvel. But you can’t tell me they designed it to have a geothermal unit and plumbing and that.”

Again he pointed to the light.

“You’ve lost me,” admitted Beauvoir.

Gamache turned to him. “In your home, in mine, there’re two walls. The exterior cladding and the interior drywall. And between the two is the insulation, and the wiring. The plumbing. The vents.”

And then it clicked for Beauvoir. “They can’t have passed the wires and pipes through solid stone. So this isn’t the outside wall,” he pointed to the fieldstones that made the wall, “there’s another wall behind it.”

“I think there must be. The wall you examined for flaws might not be the one that’s crumbling. It’s the outer wall that’s breached by roots and water. It isn’t yet noticeable inside.”

Two skins, thought Beauvoir, as they resumed their walk and stepped into the Blessed Chapel. The public face, and then the crumbling, rotting one behind.

He’d made a mistake. Hadn’t looked hard enough. And Gamache knew it.

“Excusez-moi,” a voice sang out, and the two men slowed, and turned. They were crossing the Blessed Chapel.

“Over here.”

Gamache and Beauvoir looked to their right, and there, in the shadows, stood the Dominican. Beside the plaque to Gilbert of Sempringham.

The two Sûreté men walked over.

“You looked like you have someplace to go,” said Frère Sébastien. “If I’m disturbing you we can talk later.”

“We always have someplace to go, mon frère,” Gamache said. “And if we don’t we’re trained to look as though we do.”

The Dominican laughed. “The same with monks. If you go to the Vatican we’re always hurrying down corridors looking important. Most of the time we’re just trying to find a bathroom. The sad convergence of great Italian coffee and a shocking distance between toilets in the Vatican. The architects of Saint Peter’s were brilliant, but toilets weren’t a priority. Superintendent Francoeur has told me something about the death of the prior. I wonder if we can talk some more about it? I get the feeling that while Monsieur Francoeur’s in charge, you do most of the actual investigating.”

“That’s a fair assessment,” agreed Gamache. “What questions do you have?”

But instead of answering, the monk turned to the plaque. “A long life, Gilbert had. And an interesting description.” He gestured to the writing. “I find it strange that the Gilbertines themselves, who presumably made the plaque, should make him out to be so dull. But way down here, as an afterthought, they say he defended his archbishop.” Frère Sébastien turned to Gamache. “You know who that was?”