Rosenblatt realized, too late, that his initial impression had been right. Here was a dangerous man. And he’d led him into dangerous territory.

Rosenblatt’s formidable mind raced, but kept coming back to the same place.

He could lie, but it would be found out eventually.

“The field of armament design,” said Professor Rosenblatt, and noticed that Gamache showed absolutely no surprise.

“It would have to be, wouldn’t it?” said Gamache, being equally open with Rosenblatt. “After all, why else would you be here?”

The two men stared at each other. Not challenging, not threatening each other. There was no power struggle. Just the opposite.

There was recognition.

Here was someone else best in his field. And that field was pitted, and weedy, and pocked with land mines. You didn’t get to the other side without some wisdom, and without some wiles. And without some scars.

“What are you asking me, monsieur?”

“I’m asking if you worked with Gerald Bull.”

Gamache saw the eyes flicker, wanting to drop, to break contact. But they held, and Michael Rosenblatt gave one curt nod.

“As I told your young colleague, Inspector Beauvoir, we worked at McGill at the same time, but I’m afraid I wasn’t completely honest. We did work together, not in the same department but on some of the same projects. Though no one really worked with Gerald Bull. It might start out that way, but eventually you found yourself working for him.”

“Were you working for him when he came up with the plans for the Supergun?”

“No. I left when he began using the Soviets as a back door to sell his arms. He wasn’t very smart.”

“Is that why you left? Fear you’d get caught?”

“No. I left because it was wrong. It’s one thing to design weapons for your own country, it’s another to sell them to the highest bidder. Gerald Bull was the consummate salesman, and completely without a conscience.”

“Why did you just say that he wasn’t very smart?” asked Gamache.

“He made some stupid choices, like cozying up to the Soviets. He had an outsized ego that told him he was smarter than other people.”

“The ego lied?” asked Gamache.

“Shocking, I know. Dr. Bull was bombastic. The perfect personality for a man who sold cannons and Bull was, as I said, a great salesman.”

“Why would he have the Whore of Babylon etched into the cannon? Was it a sort of calling card? A signature? Did Dr. Bull put it into all his designs?”

“Not that I know of. It was probably another sales tool. What else would appeal to a crazy despot like Saddam but a weapon etched with a symbol of the apocalypse? And one from ancient Iraq, no less. It was perfect.”