Lord Bontriomphe listened without asking questions until the commander’s narrative was finished; then he looked at the Lord High Admiral and waited expectantly.

“Huhum!” The Lord High Admiral gave a rumbling chuckle. “Yes, my lords. The connection, of course. It was this: Sir James Zwinge, Master Sorcerer and Chief Forensic Sorcerer for the City of London, was also the head of our counterespionage branch — operating under the code name of ‘Zed.’ ”

“And now,” said Lord Darcy an hour later, “I am prepared to make an arrest for the murder of Master Sir James Zwinge.”

My lord the Marquis of London remained all but motionless behind his desk. Only the slight narrowing of his eyes gave any indication that he had heard what the Chief Investigator of Normandy had said.

Lord Darcy and Lord Bontriomphe had returned to de London’s office immediately after His Majesty had dismissed the meeting at Westminster Palace. Lord Darcy could still hear the King’s last orders: “Then we are agreed, my lords. Our civilian investigators will proceed to investigate these murders as though they were in no way connected with the Navy, as though they were merely seeking a murderer. No connection must be made between the killing of Barbour and the killing of Sir James, as far as the public is concerned. Meanwhile, the Naval Intelligence Corps will be working to uncover the other contacts of Barbour, and make a minute investigation of the reports he filed with ‘Zed’ and the reports ‘Zed’ filed with the London office. There may be more evidence than we realize in those report files. Finally, we must all do our best to see that His Slavonic Majesty’s secret agents remain at least as much in the dark as we are.”

For a moment, Lord Darcy had thought that last bit of heavy sarcasm from the King had made Lord High Admiral Peter de Valera ap Smith angry. Then he had realized that the Lord High Admiral’s choked expression came from a valiant and successful attempt to smother a laugh.

By Heaven, Lord Darcy had thought, I must get to know that old pirate better.

My lord of London had been seated behind his desk reading a book when Lord Darcy and Lord Bontriomphe had entered the office. The Marquis had picked up a thin golden bookmark, put it carefully between the pages of the book, closed the book and placed it on the desktop before him. “Good morning, my lords,” he had rumbled, inclining his head perhaps an eighth of an inch. “There is a letter for you, Lord Darcy.” He had pushed a white envelope across the desk with a fat forefinger. “Delivered this morning by special courier.”

“Thank you,” Lord Darcy had murmured politely, picking up the envelope. He had broken the seal, read the three sheets of closely written paper, refolded them, replaced them in the envelope, and smiled.

“A very informative letter from — as you no doubt noticed from the seal, My Lord Marquis — Sir Eliot Meredith, my Assistant Chief Investigator. And now, I am prepared to make an arrest for the murder of Master Sir James Zwinge.”

“Indeed?” said my lord the Marquis after a moment. “You have solved the case? Without checking the evidence personally? Without questioning a witness? How extraordinarily astute — even for you, my dear cousin.”

“You are hardly one to cavil at lack of personal investigation,” Lord Darcy said mildly, seating himself comfortably in the red leather chair. “As for my witness, there is no need to question him any further. The information is before us; we have but to examine it.

The Marquis put his palms flat on his desktop, inhaled four pecks of air, and let it out slowly through his nose. “All right. Let’s hear it.”

“It is simplicity itself. So obvious, in fact, that one tends to overlook it because of the very obviousness of the killer. Consider: A man is killed inside a locked and sealed room — in a hotel full of magicians. Naturally, we are led to believe that it is black magic. Obvious. In fact, too obvious. That is exactly what we are supposed to believe.”

“How was it done, then?” asked the Marquis, becoming interested.

“Zwinge was stabbed to death right in front of the very witnesses who were there to testify that the room was locked and sealed,” Lord Darcy said calmly.

My lord the Marquis closed his eyes. “I see. That’s the way the wind blows, eh?” He opened his eyes again and looked at Lord Bontriomphe. Lord Bontriomphe looked back at him, steadily, expressionlessly. “Continue, Lord Darcy,” the Marquis said. “I should like to hear all of it.”

“As you have deduced, dear cousin,” Lord Darcy continued, “only Bontriomphe could have done it. It was he who broke the door down. He was the first one in the room. He ordered the others to stay out, to stay back. Then he bent over the unconscious body of Sir James, and, concealing his actions with his own body, sank a knife into the Master Sorcerer’s heart.”

“How did he know Sir James would be unconscious? Why did Sir James scream? What motive did Bontriomphe have?” The three questions were deliberate, almost emotionless. “You have explanations, I presume?”

“Naturally. There are several drugs in the materia medica of the adept herbalist which will cause unconsciousness and coma. Bontriomphe, knowing that Sir James intended to lock himself into his room yesterday morning, managed to slip some such drug into the sorcerer’s morning caffe — a simple job for an expert. After that, all he had to do was wait. Eventually, Sir James would be missed. Someone would wonder why he had not kept an appointment. Someone would check his room and find it locked. At last, someone would ask the management to see if something could be wrong. When the manager found he could not open the door, he would ask for official help. And, fortuitously, Lord Bontriomphe, Chief Investigator for My Lord Marquis of London, just happens to be right on the spot. He calls for an ax and…” Lord Darcy turned one hand palm up as though he were handing the Marquis the whole case on a platter, and left the sentence unfinished.

“Go on.” There was a dangerous note in the Marquis’ voice.

“The scream is easily explained,” Lord Darcy said. “Sir James was not completely comatose. He heard Master Sean knock. Now, Sean had an appointment at that time; Sir James knew it was he at the door. Aroused by the knock, he called out: ‘Master Sean! Help!’ And then he collapsed back into his drugged coma. Bontriomphe, of course, could not have known that would happen, but it was certainly a stroke of luck, even though it was completely unnecessary to his plan. If there had been no scream, Sean would certainly have known something was amiss and notified the manager. After that, everything would have followed naturally.”

Lord Darcy folded his arms, slumped back in the chair, rested his chin on his chest, and looked at the speechless, glowering de London from beneath his brows. “The motive is quite clear. Jealousy.”

“Pah!” the Marquis exploded. “Now I have you! Up to now, you have been clever. But now you show that your wits are addled. A woman? Pfui! Lord Bontriomphe may occasionally play the fool, but he is not a fool about women. I will not go so far as to say that the woman does not live whom Lord Bontriomphe could not get if he wanted her, but I will say that his ego is such that he would have no desire for a woman who did not want him or who had rejected him for another. He would not go out of his way to snap his fingers at such a woman, much less kill because of her.”

“Agreed,” said Lord Darcy complacently. “I mentioned no woman. And I was not speaking of his jealousy.”

“Of whose, then?”

“Of yours.”

“Hah! This is fatuous.”

“Not at all. Your hobby of herb cultivation, my lord, is one of the strongest passions of your life. You are an acknowledged expert and are proud of that fact. Zwinge, too, was an herbalist, but not quite in your league. Still, if you ever had any real rival in the field, it was Master Sir James Zwinge. Recently, Sir James succeeded in growing Polish devilwort from the seed instead of from cuttings, as is normally done. You have failed to do so. Therefore, out of pique, you asked Bontriomphe to remove your rival; he, out of loyalty, proceeded to do so. And there you have it, my lord: Method, Motive, and Opportunity. Quod erat demonstrandum.”