“Or her man was the seducer. You think too much, Merlin. ”

“There’s no such thing as thinking too much. It’s what makes me useful to you.”

Arthur resumed his pacing. “Go to Cornwall. Find out why Mark was there.”

“First, Morgan, I think. She and that wizened weasel of a son of hers will be easier to eliminate.”

He narrowed his eyes. “You think Mark is the villain.”

“I think there’s a good chance of it. But I’ve been wrong before.”

“I can’t imagine such a thing.”

“Don’t be sarcastic, Arthur. You must understand what that means. We have a terrible problem. He’s the military commander. A good many of the knights will be loyal to him. Removing him-arresting him-will be tricky. You need hard, absolutely irrefutable proof.”

“Find it. Whether it’s Mark we’re after or not, find it. Do whatever you want. Go to Byzantium and investigate the emperor if you must. But find me the killer.” He glared around the room. “And get me my sword back. And the Stone of Bran.”

Merlin stopped at the door. “Oh, and about that school for the squires and pages?”

“Later, Merlin.”

The mood throughout Camelot was subdued. Brit, Nimue and Merlin were all determined not to let out word that they were on the trail of the twins’ murderer. The official story was that they were simply running some errands for the king. But people knew better, or at least suspected. Maintaining an official silence was becoming difficult. And there was a certain amount of tension: who was suspected? Even the servants were on edge.

Merlin made his way back to his tower, stopping to chat with various people, nearly all of whom tried to find out why he’d gone to Corfe, what he’d found there and why he’d come back with one of the squires from Guenevere’s court. He fielded all the questions quite tactfully, so that no one realized how evasive he’d been till after he’d moved on.

He found Nimue in Petronus’s room, checking bandages. He said good morning to her then asked, “How are you feeling this morning, Pete?”

The boy was smiling. “I’m at Camelot. I’m to be Britomart’s squire. How could I not be happy?”

“Believe me, it could happen. Are your wounds giving you much discomfort?”

“They itch.”

“That’s a good sign. It means they’re healing, and quickly.”

“Good. Can I go out and exercise with the other squires?” He shifted his weight in the bed.

“You are to remain in bed and in this room until I give you permission to do otherwise. We want you well and healthy. Do you understand?”

“But I feel fine.”

“You’re to do as you’re told. We have one rebel to deal with; we don’t need another.”

“Rebel?”

Merlin had let himself forget that the boy knew nothing about the Stone of Bran and the murders, and that he’d decided not to tell him yet. Nimue covered his slip. “I’ll tell you about it later, Pete, all right?”

Merlin asked her to join him in his study, and they climbed the spiral stairs together.

“I’ll prepare a calmative potion for you. Put it in his food or his drink and it will make him less restless.”

She laughed. “And easier to control?”

“To the extent boys that age can be controlled at all, yes. And I’ll prepare a salve to help his wounds heal. Have you had a chance to talk with Greffys?”

“Just for a moment or two. I don’t think he’s found out much.”

“He hasn’t been talking to the servants?”

She nodded. “He has, but he’s out of his depth.”

“Then it’s just as well you’re staying behind. Have him introduce you to the more talkative among them and see what you can learn. But remember, be discreet. Be indirect. We don’t want to put anyone on his or her guard.”

“I know what to do.”

“I want to move quickly. Brit and I will leave to visit Morgan tomorrow morning. If you can find the girl who was with Lancelot, or at least someone who knows definitely that he was with a girl, we will have eliminated one suspect, at least.”

“If. Do you think there is such a girl?”

“I think Lancelot is probably too dim to have invented a story like that. What would be the point?”

“Male boasting. Never underestimate the power of the male ego.”

“See if you can find out, one way or the other.”

"But Merlin… why would a girl from the kitchen…?”

“Don’t be naïve, Nimue. Knights, lords and kings have their way with women of the lower ranks. Remember Anna? It is called privilege. If there is something you should never underestimate, it is the vulnerability of women.”

“Vulnerability? There might be another name for it. But I’m more grateful than ever to be disguised as Colin.”

He smiled. “I’m glad you are, too. You are the most apt pupil I could want.”

“Why, thank you, Merlin.” She blushed.

“Didn’t you know I think so?”

“You’ve never bothered to say it before. Men.”

He crossed to his table and found a sheet of paper. “Here. I want you to try and find the chemicals on this list for me. You should be able to locate them in the armory, I think. Tell the armorers they’re for me.”

She took the list and read it, puzzled. “Acids?”

“I’m no swordsman. And this is getting dangerous. We can’t count on our villain mistaking someone else for one of us a second time. I’ll be in the stables, at the blacksmith’s forge. I have some glass-blowing to do.”

Arthur wanted Merlin and Brit to take an armed escort. He told them so at dinner in the refectory. Merlin insisted that would only attract attention. “We’ll be safer traveling on our own.”

“Nonsense. You’re both ministers of the state. And you’re much too valuable to put yourselves at risk. Suppose someone comes at you with a sword? Look at what happened to Petronus. You’re an able man, Merlin, but you aren’t much good in a fight.”

Brit bristled at this. “And I, of course, am completely useless.”

“Britomart, we are dealing with a cunning villain here. Possibly a mad one. I won’t have you vulnerable when it is avoidable. You will travel by carriage, not by horse, and you will have an escort of soldiers. I’ll have Accolon lead them. This is not debatable.” He turned and walked away from them.

And so the next morning a carriage and driver were provided, along with a detachment of six men on horse-back, including Accolon. Brit and Merlin stepped inside their conveyance unhappily, and with a lurch it began to move. The horses’ hooves clattered loudly on the courtyard stones.

Brit felt her skill as a knight was in question. “I’ve beaten most of the knights here in single combat.” She sulked. “Including Arthur himself. He knows I can take care of myself.”

“You mustn’t take this personally, Brit. He’s underestimating me, too. But it is a matter of public policy. If we bring Mark down, you will be the country’s top military officer. If I were advising the king, I’d tell him to do exactly as he’s doing.”

“How, exactly, is he underestimating you?” She asked the question with a sneer in her voice.

“He is assuming the only way to defend oneself is though main force.”

“Isn’t it? Merlin, you’re well into middle age. And you’ve never been an athlete. How could you possibly defend yourself from an attacker?”

He smiled, reached into his pocket and produced a handful of small glass globes. Each of them contained some clear fluid. “With these.”

“With marbles? Merlin, you’re not serious.”

“These are made from very thin, very fragile glass. And inside each of them is a quantity of aqua regia.”

“Acid? You mean to fight off an insane killer with marbles full of acid?”

“Aqua regia is not simply acid-it is the strongest acid known to science. It can dissolve gold. If someone comes at me with sword drawn, it will stop him, believe me.”

“You’re making a fairly big assumption. Suppose he attacks from a distance? With spears or arrows?”

“No defense is perfect, Brit.”

“I’ll say.” She smirked. “Why don’t you leave your safety in my hands?”