“He’s not there,” he whispered.

“Has he found it?” Lacoste asked.

“One way to find out,” said Gamache. He motioned to Beauvoir to go around back while he and Lacoste, bent over, ran along his verandah to the front door.

Isabelle Lacoste drew her gun and opened the door slowly, carefully. Then stepped inside. Scanning the room. It was empty. She moved swiftly to the study while Gamache went down the hall to one of the bedrooms.

Lacoste opened the desk drawer in the study, then closed it and left, meeting Gamache in the living room.

“Beauvoir’s gun’s missing from his bedroom,” he said.

“The firing mechanism for the Supergun is also missing.” She waved toward the study.

The verandah door opened and Jean-Guy called in, “He’s in the woods. I can hear him.”

They ran out the door, a few paces behind Jean-Guy, who was racing between the trees. He forced himself to slow down now and then to listen. To make sure they were still on the right track. It was pitch-dark but a man running through the autumn forest, through the dead and withered leaves, made a lot of noise. And that’s what they followed.

It was a headlong pursuit. It was no use trying to hide the fact they were after him. It was a race now, through the dark woods. After the man who’d murdered Laurent Lepage. The man who’d murdered Antoinette Lemaitre.

The man who, with the stolen firing mechanism, would murder millions.

Up ahead the running stopped. But they did not. They kept going, straight into the raised gun.

*   *   *

He had them in his sights. He waited until he couldn’t miss, and then pulled the trigger.

But nothing happened. He pulled it again. But by then it was too late, they were on him, Isabelle Lacoste tackling him, and Beauvoir piling on.

Armand Gamache, a few paces behind the younger agents, pulled out his device and turned on the flashlight app. And there, in the beam, was their murderer. The man who’d searched, like a pirate for treasure, like a leech for someone else’s blood, for decades. And when he’d finally found Project Babylon, all it brought was death.

In the beam of light was Brian Fitzpatrick.

CHAPTER 44

Adam Cohen had arrived back and now sat in the bistro by the fire, picking the label off his beer. He’d been offered a stiff cognac, and had taken a sip because Gamache had one and it looked so good. But while it looked like maple syrup, it tasted like turpentine.

They had the bistro to themselves. It was late and Olivier and Gabri had cleaned up and left, handing the key to Gamache with the request that they lock up when they were done.

Now it was just the Sûreté officers, helping themselves to the chips and mixed nuts and the drinks.

Jean-Guy tossed a birch log onto the fire and the embers exploded then drifted up the chimney. They stared, mesmerized.

“But why didn’t the gun fire?” Adam Cohen asked. “Brian was pointing it right at you.”

“Seems the firing mechanism was missing from that too,” said Lacoste. “We knew he didn’t have a gun, and we suspected he’d look for one in the Gamaches’ home, so Inspector Beauvoir deliberately left his behind, in his nightstand.”

“Why not just take out the bullets?”

“He might’ve checked,” said Beauvoir. “But no one thinks to check the firing pin.”

“We learned that trick from Guillaume Couture,” said Isabelle Lacoste. “He took the firing mechanism out of the Supergun for the same reason. So that no one else could use it.”

“He had a conscience after all,” said Gamache. “But it took the murder of Gerald Bull for him to come to his senses and see that this was not just a job, not some challenge or a problem to be solved as elegantly as possible. What he’d created would kill hundreds of thousands of people.”

“The plans were missing,” said Jean-Guy. “He might’ve thought Bull destroyed them himself, or he might’ve even suspected that Fleming had stolen them.”

“If he did suspect, he probably didn’t want to confront the man,” said Isabelle.

“Why not?” asked Cohen.

“Would you?” she asked.

The young agent shook his head. He still looked pale and shaken from his encounter with John Fleming.

“All Dr. Couture could do to disable Big Babylon was take out the firing mechanism,” said Lacoste. “He must’ve taken it home and made it look like two separate pieces. He told his niece about it, but Antoinette didn’t pay much attention until Laurent found the gun, and then was killed.”