While unexpected, the question didn’t totally surprise Gamache.

“It’s the first musical notation. Before there were notes there were neumes.”

“Oui. We tend to think the five-line staff was always there. Clefs, treble clefs, notes and half notes. Chords and keys. But they didn’t just spring into the world. They evolved. From neumes. They were meant to mimic hand movements. To show the shape of the sound.”

Frère Sébastien lifted his hand and moved it back and forth, up and down. It glided through the chilly autumn air, graceful. As he moved his hand he hummed.

It was a lovely voice. Clear. Pure. With a soulful quality. And despite himself, Gamache felt himself drifting along with it. Entranced by the movement of the hand, and the calming sound.

Then the voice, and the hand, stopped.

“The word ‘neume’ comes from the Greek for ‘breath.’ The monks who first wrote down the chants believed that the deeper we breathe the more we draw God into ourselves. And there’s no deeper breath than when we’re singing. Have you ever noticed that the deeper you breathe, the calmer you get?” the monk asked.

“I have. As have Hindus and Buddhists and pagans for millennia.”

“Exactly. Every culture, every spiritual belief, has some form of chanting, or meditation. And at their core is the breath.”

“So where do neumes come in?” Gamache asked. He was leaning toward the Dominican, holding his large hands together for warmth.

“The first plainchants were learned orally. But then, around the tenth century a monk decided to write them down. But to do that he needed to invent a way of writing music.”

“Neumes,” said the Chief, and the monk nodded.

“For three centuries, generations of monks wrote down all the Gregorian chants. To preserve them.”

“So I’ve heard,” said Gamache. “Many monasteries were given Books of Chants.”

“How’d you know?”

“They have one here. Apparently not one of the more remarkable.”

“Why do you say that?”

“I don’t,” said Gamache. “The abbot told me. He says most are illuminated editions. Very fine. But he suspects since the Gilbertines were a minor order and very poor, they ended up with the tenth-century equivalent of a factory second.”

“Have you seen the book?”

Frère Sébastien leaned toward Gamache. The Chief Inspector opened his mouth to speak, then shut it again and examined the Dominican.

“That’s why you’re here, isn’t it?” Gamache finally said. “Not to find the Gilbertines, but to find their book.”

“Have you seen it?” Frère Sébastien repeated.

“Oui. I held it.” There was no use denying it. The book wasn’t exactly a secret.

“My God,” Frère Sébastien exhaled. “Dear God.” He shook his head. “Can you show me? I’ve been looking all over for it.”

“All over the monastery?”

“All over the world.”

The Dominican rose and whacked the dirt and twigs off his white robes.

Gamache also got up. “Why didn’t you ask the abbot or any of the monks?”

“I thought they’d probably hidden it.”

“Well, they didn’t. It normally sits on the lecturn in the Blessed Chapel, for all the monks to consult.”

“I didn’t see it there.”

“That’s because one of the monks has been keeping it with him. Studying the chants.”

As they talked they’d made their way back to the monastery, and stopped in front of the thick wooden door. Gamache knocked and after a moment they heard the bolt slide back and the key turn in the lock. They stepped in. After the chill outside, the abbey felt almost warm. The Dominican was halfway down the hall before Gamache called him back.

“Frère Sébastien?”

The monk stopped and turned, impatient.

Gamache pointed to Frère Luc, standing in the porter’s room.

“What is it?” And then Frère Sébastien realized what Gamache was telling him. The Dominican began walking back, quickly at first, his pace slowing as he got closer to the porter’s room.

Frère Sébastien seemed reluctant to take that last step. For fear, perhaps, of disappointment, Gamache thought. Or perhaps he realized he didn’t really want the search to end. Because then what would he do?

If the mystery was solved, what would be his purpose?