“Which was strange,” said Cohen. “He admits he’s American, a draft dodger. There should have been something. But then I tried the Judge Advocate General’s office. It’s the legal part of the U.S. Army, based in Washington, and look what I found.”

He handed a printout to Chief Inspector Lacoste, who read it, her face growing graver and graver. After taking a deep breath, she handed it to Beauvoir, and then turned to Cohen.

“Show me.”

She followed him to his computer while Beauvoir read, then handed the page to Gamache.

Al Lepage’s real name was Frederick Lawson. A private in the U.S. Army.

“Not a draft dodger,” said Gamache, looking at Beauvoir over his reading glasses. “A deserter.”

“Keep reading,” said Jean-Guy, his face solemn.

Gamache did. He could feel his cheeks grow cold, as though a window had been left open a crack and an ill wind had slipped in.

“Not just a deserter,” said Beauvoir, when Gamache had lowered the page to the table. “He was about to be tried for his part in a massacre.”

“The Son My Massacre,” said Gamache. “You’re too young to remember, but I do.”

Isabelle Lacoste had sunk into a chair and was scrolling through photographs on Cohen’s computer. Beauvoir joined her, as did Gamache, reluctantly. He’d seen them once before, as a young man, barely more than a child. Photographs of the atrocity were on the evening news in the late 1960s. It was something you never forgot.

The four of them, three seasoned homicide detectives and one rookie, looked at the pictures, almost too horrific to comprehend. Hundreds and hundreds of bodies. Little limbs. Long dark hair. Bright clothing put on by men, women, children, infants that morning, not knowing what was approaching over the ridge.

“Al Lepage was one of the soldiers who did this?” asked Lacoste.

“Frederick Lawson was,” said Agent Cohen. “And he became Al Lepage when he came across the border.”

“Not running from a war he didn’t believe in, but from justice,” said Beauvoir.

Beside him he heard Gamache take a deep, deep breath and then sigh.

“We now know Al Lepage’s capable of killing a child,” said Beauvoir.

“What do we do with this information?” Adam Cohen asked Chief Inspector Lacoste.

“We keep it to ourselves for now,” said Lacoste. “Until our investigation’s over. And then we decide what to do.”

As they walked back to the conference table she glanced at Gamache, who gave her a subtle nod. It was what he’d do.

“What’s this?” asked Beauvoir, reading another printout.

“That’s the other thing I found,” said Cohen. “You asked me to look into Dr. Couture’s will, which I did. He left everything to his niece. That’s pretty clear, but then I got to wondering what ‘everything’ was. The contents of his home, a twenty-thousand-dollar life insurance policy and a bit of savings, and the house itself. But the real estate search showed he once owned another property.”

“Just outside Three Pines?” asked Lacoste. “Where the gun is?”

“No. A distance from here,” said Agent Cohen. “In a place called Highwater.”

“Ahhhh,” said Gamache, putting his hands together on the table. “That is interesting.”

“Isn’t that where the CSIS agents went the other day?” asked Lacoste.

“And where I went after leaving you at the Knowlton Playhouse,” said Gamache. “I retraced their route. And this is what I found.”

He handed his device with the pictures on it to Lacoste, and described what he’d done. And what he’d seen.

“But what is it?” asked Lacoste, handing the device to Beauvoir via Cohen, who snuck a quick peek.

“You remember the redacted information Reine-Marie found on Gerald Bull?” asked Gamache. “Most of the interesting information had been blacked out, but there was the one word the censors missed.”

“Superguns,” said Beauvoir, his brows rising. “Ssssszzzz.”

“Plural.” Gamache nodded toward the device in Jean-Guy’s hand. “I think that was another one of Gerald Bull’s, or Dr. Couture’s, missile launchers. A much smaller version, maybe a test model before building the real thing.”

“Project Babylon wasn’t one gun, but two,” said Lacoste. “And the land belonged to Dr. Couture?”

“Until he sold it to a numbered company,” said Cohen. “I’m trying to track it down.”