“A very good choice,” said Armand, leaning toward her conspiratorially.

Mary Fraser all but blushed, and then to cover her reaction she pointed to the papers by Lacoste’s hand.

“Are those about Project Babylon?”

“A little. Mostly they’re about Gerald Bull.” Lacoste held them up. “Redacted, so most of the information on Project Babylon has been removed.”

“Where did you get them?” asked Rosenblatt, taking a sheet and scanning it.

“Archives.”

“How did you get them?” he asked. “I’ve been trying for years.”

“And if you’d joined the Sûreté you might’ve been successful,” said Lacoste. She caught Gamache’s eyes and saw his appreciation. She was not going to mention Madame Gamache.

Rosenblatt frowned, but didn’t say anything. Mary Fraser picked up the pages and scanned them, pausing at the black-and-white photograph of Gerald Bull.

“Did you ever meet him?” Lacoste asked, and Mary Fraser shook her head.

“This is a common photo of him though,” she said. “Just about the only one I’ve seen. For a man with an outsized ego, he didn’t like to have his picture taken.”

Mary Fraser put the photo down and turned to the typed pages.

“Interesting reading,” said Isabelle Lacoste. “The details are blacked out, but the reports confirm that Gerald Bull would sell anyone anything. Not just the Iraqis.”

“I think it’s over to you,” Rosenblatt said to the CSIS agents. “Unless you’d like me to answer.”

Mary Fraser looked annoyed, but realized she really had no choice.

“The papers are correct. Gerald Bull went completely off the rails in Brussels. He took on contracts with anyone and everyone. All the legitimate powers who once worked with him backed off. He was like the Black Death.”

“Tell them about the Soviets,” said Rosenblatt, obviously enjoying himself.

Delorme shot him what he must’ve thought was a withering look but managed to be just comical.

“Bull used the Soviets and South Africans as conduits for his weapons and designs,” said Fraser. “But as you know, his biggest contract was with the Iraqis. He was completely amoral.”

“Let’s not be disingenuous here,” said Lacoste. “We’ve been doing our own research. Saddam got a lot of his weapons from the West. Dr. Bull was far from alone.”

“The region’s a quagmire,” Mary Fraser admitted. “We supplied Saddam, but stopped when we realized what he was capable of. Gerald Bull did not. He saw a business opportunity, a market, and he jumped in. We deeply regret selling Saddam any weapons, but who knew he’d turn out to be a sociopath?”

Professor Rosenblatt looked about to say something, so Sean Delorme jumped in.

“No one’s proud of the choices we made, but at least we were trying to keep order. But Gerald Bull was a whole other beast. He was beyond any form of control. He’d slipped below the official channels and was into the dark region of arms suppliers. There were no rules or laws, and no boundaries. If governments were making a mess of it, you can imagine the damage the arms dealers were doing. We’re pretty sure the gun was destined for the Iraqis. Bull apparently convinced Saddam that he could make him the only superpower in the region.”

“And you had no idea this was happening?” asked Beauvoir.

Sean Delorme shook his head and a long strand of the combover came loose. “Informants told us they thought Gerald Bull was having parts of the cannon made in different factories around the world, but he was killed before he could assemble it.”

“Then what’s that?” Beauvoir pointed toward the forest.

The CSIS agents shook their heads in unison. More combover came loose, exposing Sean Delorme’s skull if not his thoughts.

“I don’t know,” said Mary Fraser. “I mean, we know what it is. It’s a Supergun. But we don’t know how it got there.”

“And why someone had to murder a nine-year-old boy to keep it quiet,” said Gamache.

“Thank God it doesn’t work,” said Lacoste.

“But why doesn’t it work?” asked Professor Rosenblatt. “Don’t get me wrong, I’m as relieved as you, but, well…”

“Where’s the key?” said Beauvoir.

“The what?” asked Delorme.

“The key,” said Professor Rosenblatt. “The missing firing mechanism.”

“But there’s something else missing,” said Beauvoir. “Something you haven’t mentioned.”