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.”

“What?” asked Delorme.

“The plans,” said Professor Rosenblatt.

He no longer looked like he was enjoying this. Now he was deadly serious, his eyes bright and his voice grave. This was not a man who was there for amusement.

“Oui,” said Beauvoir, nodding. “When I make a model plane, I have plans. You can’t tell me Gerald Bull made it up as he went along. He might’ve been a genius, but no one could do that. He must’ve had drawings.”

The CSIS agents fell silent.

“Well?” asked Beauvoir.

“No plans were ever found,” said Mary Fraser. “And not for lack of trying. Dr. Bull’s apartment had been broken into several times before he was killed. As a warning for him to stop his activities, but also, we suspect, to search for his schematics.”

“You suspect?” said Lacoste. “So it wasn’t CSIS?”

“No. We don’t know who broke into his home.”

“Probably the same people who killed him,” said Delorme.

“It was a professional hit,” said Mary Fraser, the words coming out with disconcerting ease. And familiarity. “Bullets to the head to be sure of the kill.”

And Isabelle Lacoste looked with fresh eyes at this middle-aged, slightly drab woman. Was she familiar with this method through training or personal experience? Was it possible she knew much more about the murder of Gerald Bull than she was saying? This conversation was obviously redacted.

Lacoste did a quick calculation. Mary Fraser was probably in her mid-fifties. Gerald Bull was murdered in Brussels twenty-five years ago.

Fraser would have been in her mid-twenties.

It was possible. Most soldiers were that age, or younger.

“Are you sure he’s dead?” asked Gamache, and all eyes swung to him.

“Pardon?” said Mary Fraser.

“Gerald Bull. Did CSIS see the body? Did anyone at the Canadian Embassy identify it?”