“That a giant gun had been built, with our knowledge, on the border with the U.S. thirty-five years ago?” asked Mary Fraser. “Not exactly dinner table conversation.”

“This isn’t a dinner table,” Lacoste snapped. “This is a murder investigation. Multiple murders, and you had valuable information.”

“We had nothing,” said Mary Fraser. “How does it help find your killer to know about a long-abandoned and failed experiment?”

Jean-Guy reached into the evidence box and brought out the pen set and the bookends and placed them on the table in front of him, then, without a word, Isabelle Lacoste picked them up, manipulating them.

The CSIS agents watched with mild curiosity that became astonishment as they realized what she was doing.

After the final piece clicked into place, she put it on the table in front of Mary Fraser. It was Sean Delorme who picked it up and examined it.

“The firing mechanism?” he finally asked.

“Oui,” said Lacoste. “In case you didn’t know, that”—she thrust her finger toward the assembled piece—“is a pretty good representation of a homicide investigation. All sorts of apparently unrelated and unimportant pieces come together to form something lethal. But we can’t solve a case if people are keeping information from us.”

“Like a big goddamned gun on the top of a hill,” said Beauvoir. “The baby brother of the one in the woods.”

Mary Fraser took this in but seemed unmoved, and Lacoste suspected it was because to her secrets were as valuable as information. She was not designed to give up either.

“Where did you find it?” He held it up.

When Lacoste didn’t answer, he looked back down at the thing in his hand. “Well, wherever it was, I’m glad you did. This could’ve been big trouble.”

“Big trouble,” Beauvoir repeated. “Maybe that’s why it’s called Big Babylon.”

“You think this is funny?” Mary Fraser asked in exactly the same clipped tone his teacher had used when he’d hit Gaston Devereau in the nose with a baseball. All that was missing was the “young man?”

“Do you know what the bomb that destroyed Hiroshima was called?” she asked, confirming Beauvoir’s image of her.

“Big Boy.” Mary Fraser let that sink in. “Big Boy killed hundreds of thousands. Big Babylon would do worse. Unlike you, Gerald Bull knew his history and knew his clients would too. He also knew the power of symbolism. He comes from a long and proud tradition of making a weapon even more terrifying by appearing to belittle it.”

“Proud tradition?” asked Lacoste.

“Well, a long one.”

Lacoste walked to the window. “If it’s so dangerous, why haven’t you called in the army? The air force?” She scanned the skies. “There should be helicopters overhead and troops on the ground guarding the thing.”

She turned back to the CSIS agents.

“Where is everyone?” she asked.