Pendergast did not bother to listen to the rest of the message. With a jab of his finger, he deleted it and hung up the phone. Only then did he sit down behind his desk, put his elbows on the polished surface, rest his chin on tented fingers, and stare off into space, seeing nothing.

Constance Greene was seated in the music room of the Riverside Drive mansion, playing softly on a harpsichord. It was a gorgeous instrument, made in Antwerp in the early 1650s by the celebrated Andreas Ruckers II. The beautifully grained wood of the case had been edged in gilt, and the underside of the top was painted with a pastoral scene of nymphs and satyrs cavorting in a leafy glade.

Pendergast himself had little use for music. But — while Constance’s own taste was by and large limited to the baroque and early classical periods — she was a superb harpsichordist, and Pendergast had taken enjoyment in acquiring for her the finest period instrument available. Other than the harpsichord, the room was simply and tastefully furnished. Two worn leather armchairs were arranged before a Persian carpet, bookended by a brace of identical standing Tiffany lamps. One wall had a recessed bookcase full of sheet music of seventeenth- and eighteenth-century composers in urtext editions. The opposite wall held half a dozen framed pages of faded handwritten scores, original holographs of Telemann, Scarlatti, Handel, and others.

Not infrequently, Pendergast would glide in, like a silent specter, and take a seat in one of the chairs while Constance was playing. This time, Constance glanced up to see him standing framed in the doorway. She arched an eyebrow, as if to ask whether she should cease playing, but he simply shook his head. She continued with the Prelude no. 2 in C-sharp Minor from Bach’s Well-Tempered Clavier. As she worked her way effortlessly through the short piece, wickedly fast and dense with ostinato passages, Pendergast did not take his accustomed seat, but instead roamed restlessly around the room, plucking a book of sheet music from the bookcase, leafing through it idly. Only when she was done did he move over to one of the leather armchairs and sit down.

“You play that piece beautifully, Constance,” he said.

“Ninety years of practice tends to improve one’s technique,” she replied with a ghost of a smile. “Any further word about Proctor?”

“He’ll pull through. He’s out of the ICU. But he’ll need to spend a few more weeks in the hospital, and then a month or two more in rehabilitation.”

A brief silence settled over the room. Then Constance rose from the harpsichord and took a seat in the opposite armchair. “You’re troubled,” she said.

Pendergast did not immediately reply.

“Naturally, it’s about Alban. You haven’t said anything since — since that evening. How are you doing?”

Still Pendergast said nothing, continuing to leaf idly through the book of sheet music. Constance, too, remained silent. She, more than anyone, knew that Pendergast intensely disliked discussing his feelings. But she also sensed instinctively that he had come to ask her advice. And so she waited.

At last, Pendergast closed the book. “The feelings I have are those that no father would ever wish for. There’s no grief. Regret — perhaps. Yet I’m also conscious of a sense of relief: relief that the world will be spared Alban and his sickness.”

“Understandable. But… he was your son.”

Abruptly, Pendergast flung the volume aside and stood up, pacing back and forth across the carpet. “And yet the strongest sensation I feel is bafflement. How did they do this? How did they capture and kill him? Alban was, if anything, a survivor. And with his special gifts… it must have taken enormous effort, expenditure, and planning to get him. I’ve never seen such a well-executed crime, one that left only the evidence meant to be left and no more. And most puzzling of all—why? What is the message being conveyed to me?”

“I confess I’m as mystified as you are.” Constance paused. “Any results from your inquiries?”

“The only real evidence — a piece of turquoise found in Alban’s stomach — is resisting identification. I just had a call about it from Dr. Paden, a mineralogist at the Museum of Natural History. He doesn’t seem confident of success.”

Constance watched the FBI agent as he continued to pace. “You mustn’t brood,” she said at last in a low voice.

He turned, made a dismissive motion with one hand.

“You need to throw yourself into a fresh case. Surely there are plenty of unsolved homicides awaiting your touch.”

“There is never a shortage of jejune murders out there, unworthy of mental application. Why should I bother?”

Constance continued to watch him. “Consider it a distraction. Sometimes I enjoy nothing more than playing a simple piece written for a beginner. It clears the mind.”

Pendergast wheeled toward her. “Why waste my time with some trifle, when the great mystery of Alban’s murder is staring me in the face? A person of rare ability seeks to draw me into some sort of malevolent game of his own devising. I don’t know my opponent, the name of his game — or even the rules.”

“And that’s exactly why you should immerse yourself in something totally different,” Constance said. “While awaiting the next development, take up some small conundrum, some simple case. Otherwise… you’ll lose your equilibrium.”

These last five words were spoken slowly, and with conviction.

Pendergast’s gaze drifted to the floor. “You’re right, of course.”

“I suggest this because — because I care for you, and I know how obsessive and unhappy this bizarre case could make you. You’ve suffered enough.”

For a moment, Pendergast remained still. Then he glided forward, bent toward her, took her chin in one hand, and — to her great astonishment — kissed her gently.

“You are my oracle,” he murmured.

Vincent D’Agosta sat at the table in the small area he had claimed as his forward office in the New York Museum of Natural History. It had taken a heavy hand to pry it loose from the Museum’s administration. Grudgingly they had given up a vacant cubby deep within the Osteology Department, which was thankfully far from the reeking maceration tanks.

Now D’Agosta listened as one of his men, Detective Jimenez, summarized their review of the Museum’s security tapes for the day of the murder. In a word: zip. But D’Agosta put on a show of listening intently — he didn’t want the man to think his work wasn’t appreciated.

“Thank you, Pedro,” D’Agosta said, taking the written report.

“What next?” Jimenez asked.

D’Agosta glanced at his watch. It was quarter past four. “You and Conklin knock off for the day, go out and have a cold one, on me. We’ll be holding a status meeting in the briefing room tomorrow morning at ten.”

Jimenez smiled. “Thank you, sir.”

D’Agosta watched his departing form. He’d have given just about anything to join the guys in hoisting a few. But no: there was something he had to do. With a sigh, he flipped quickly through the pages of Jimenez’s report. Then, putting it aside, he pulled his tablet from his briefcase and began preparing a report of his own — for Captain Singleton.

Despite his team’s best efforts, and two days during which more than a hundred man-hours of investigative work had been expended, not a single decent lead had surfaced in the murder of Victor Marsala. There were no eyewitnesses. The Museum’s security logs had picked up nothing unusual. The big question was how the damn perp had gotten out. They’d been beating their heads against that question from the beginning.

None of the enormous amount of forensic evidence they’d gathered was proving relevant. There appeared to be no good motive for murder among Marsala’s co-workers, and those who bore even the faintest grudge against him had ironclad alibis. His private life was as boring and law abiding as a damn bishop’s. D’Agosta felt a prickling of personal affront that, after all his time on the job, Captain Singleton should toss him an assignment like this.