“No, nothing yet,” she said, and hanging up, she went back to them. Like the play, she knew her answer was right in front of her if only she could find it.

Isabelle Lacoste had gone over and over the notes. The interviews. The evidence from both murders.

Antoinette Lemaitre had been killed either by someone she’d invited into her home, or when she’d surprised an intruder. It was someone who knew about Project Babylon, and knew Brian would be in Montréal. Someone who knew that her uncle was Guillaume Couture and that Dr. Couture had been Gerald Bull’s main designer. Perhaps even knew he was the real architect of Project Babylon.

Someone who thought the plans were hidden in his home. Someone who might’ve been looking for them for years.

The gun couldn’t be sold. Not anymore. But the plans could.

Lacoste stopped herself.

Sidetracked by the goddamned plans again, she thought, and gave a heavy sigh.

But still, she’d come close, before veering off. Where had she gone astray?

All right, she told herself. Let’s set aside Antoinette’s murder and go back to the first one. Laurent’s death.

She herself had been in the bistro when the boy had raced in with yet another ridiculous story, so clearly a product of his imagination.

Isabelle Lacoste tried to remember what he’d said and done.

Laurent had run in and come up to their table, jabbering excitedly, announcing to the room that he’d found a huge gun in the woods. With a monster on it.

When no one paid attention, Laurent had tugged at Gamache’s arm to follow him.

Instead, the Chief had driven him home. In the car, Laurent had entertained him with more tales about the gun, and about winged monsters and alien invasions and whatever else his fertile imagination produced.

A day later, Laurent was dead.

Who else had he told? His parents. His father. The one person who would know it wasn’t a fantasy, though Lepage claimed not to know what Dr. Bull and the others were building. Was that one more lie in a life that was itself a fabrication? Did he kill his own son to shut him up, knowing that if the massive gun was found, with his etching, questions would be asked and Frederick Lawson might be revealed?

Is that what happened? Or had Laurent run into someone else in the hours after Gamache had dropped him off? Someone who knew Laurent was telling the truth. Someone who had Laurent show him the gun, and then killed him there and placed his body by the side of the road, to make it look like an accident.

She was missing something. Or misinterpreting something. There was something she wasn’t seeing.