“But the stick wasn’t with him,” said Reine-Marie, jumping in to help her husband.

“So who killed Antoinette?” asked Brian. “Was it the same person?”

“Well, that brings us to Project Babylon,” said Lacoste.

“Whoever killed Antoinette obviously knew that her uncle was Guillaume Couture,” said Jean-Guy Beauvoir, taking up the story. “And knew he worked with Gerald Bull. He might not have known Dr. Couture was the architect of Project Babylon, but probably suspected. It had long been rumored that Gerald Bull was more salesman than scientist. When no plans were found in his Brussels apartment or anywhere associated with Dr. Bull, most intelligence organizations and arms dealers gave up. They figured Project Babylon was a bust and its creator was both delusional and dead. But there were some people who suspected that Gerald Bull was telling the truth. Maybe even more than suspected. Maybe they knew because they were in the area when it was being built. And so when Laurent found the gun, this person believed him. And knew if the plans for Project Babylon were anywhere, they’d be in Guillaume Couture’s old home.”

As Beauvoir spoke, first Myrna, then Reine-Marie and finally the rest began to glance over to the only one who fit the description. Who was in Three Pines when the massive weapon was being constructed. And who was in the bistro when, thirty years later, Laurent found it.

Monsieur Béliveau.

The grocer sat perfectly contained, apparently oblivious to the looks, to the facts that were beginning to pile up around him.

“The other possibility is that it was someone from the outside,” Armand Gamache continued. “Someone who didn’t necessarily know Gerald Bull but knew about Project Babylon. It was, after all, a kind of open secret, with more and more information seeping out after Bull’s death. Project Babylon and its murdered creator became a curiosity, a sort of cautionary tale. But for some, as Professor Rosenblatt said, it was more than that. It became an obsession. Suppose Gerald Bull was finally telling the truth? The plans would be worth hundreds of millions of dollars. And finally, after years of patiently looking, of keeping their ears open for any nugget of information, they heard something significant. A little boy had found a great big gun. In the woods. Not far from Guillaume Couture’s home.”

“Are you suggesting someone had been looking for Project Babylon for thirty years?” asked Clara.

Isabelle Lacoste leaned forward, and everyone in the circle did too. Listening intently, drawn into the story.

“What would people do for power? For wealth?” she asked. “People spent their lives panning for gold, believing they’d find the mother lode. Some people spend all their spare time tinkering in the basement, trying to perfect an invention. Some sit day and night in front of one-armed bandits, thinking any moment they’ll hit the jackpot. People spend their lives writing a book, or looking to cure cancer.”

She looked over at Gamache and Beauvoir.

“We have colleagues who’ve spent all their spare time trying to crack a decades-old case. Rational people do become obsessed. And Project Babylon has every element necessary to grab and hold someone. Power and wealth beyond imagining. Is that worth years of work? Decades? Maybe not to you, or me. But to some, yes. The payoff is life-changing.”

“And all you need to do is be willing to take a few lives along the way,” said Beauvoir.

Eyes that had been glancing over to Monsieur Béliveau now shifted. To the one person in the room who had admitted to spending years researching Gerald Bull. Had even known the man. And known Guillaume Couture. Probably realized Couture was the architect of Project Babylon, and might even have known Antoinette was his niece.

And who lived nearby.

Michael Rosenblatt looked at them, smart enough to recognize what those glances meant. Smart enough to recognize that the facts were building a wall around him.

“But he stepped in front of Armand,” said Reine-Marie, taking her husband’s hand. “To protect him. He would never have done that if he’d killed Laurent and Antoinette.”

“Merci, madame,” said the elderly professor.

But while he said nothing, Armand wondered if that was true. He was glad Delorme hadn’t fired, but he should have. As soon as those plans hit the flames, Sean Delorme should have shot.

But hadn’t.

“So who killed Laurent and Antoinette?” Reine-Marie asked. “Do you know?”

“I’m waiting for more information,” said Lacoste. “We have our suspicions.”

“And so do I,” said Ruth. “I suspect you still have no idea.”