Master Sean brightened. “That’s good of you, my lord! But you’ll have to get me out o’ this plush cell if we’re to get the job done!”

“Hah!” Lord Darcy shot suddenly to his feet. “My dear Master Sean, that problem has, I think, already been solved — although it may take a little time to make the… er… proper arrangements. And now I shall bid you good night; I shall see you again tomorrow.”

The fog had thickened in the courtyard below the high, embattled walls surrounding the Tower of London, and beyond the Water Lane gate the world seemed to have disappeared into a wall of impalpable cotton wool. The gas lamps in the courtyard and above the gate seemed to be shedding their light into nothingness.

“Had you no one waitin’ for you, your lordship?” asked the Sergeant Warder as he stood on the steps with Lord Darcy.

“No,” Lord Darcy admitted. “I came in a cab. I must confess I failed to check with the weather prognostication. How long is the fog to last?”

“According to the chief sorcerer at the Weather Office, your lordship, it isn’t due to break up until five minutes after five o’clock in the morning. It’s to turn to a light drizzle, which will clear at six twelve.”

“Well, I certainly can’t stay here until sun-up,” Lord Darcy said ruefully.

“I’ll have the man at the gate see if he can’t whistle you up a cab, your lordship; it’s still fairly early. You can wait in the outer—” He stopped. From somewhere in the fog that choked Water Lane came the clatter of hooves and the rattle of wheels, becoming increasingly louder.

“That may be a cab, now, your lordship!” He raised his authoritative voice to a commanding bellow: “Warder Jason! Signal that cab!”

“Yes, Sergeant!” came a fog-muffled voice from the gate, followed immediately by the shrill beep! beep! beep! of a cab whistle.

“I fear we are to be disappointed, Sergeant,” Lord Darcy said. “Your ears should tell you that the vehicle approaching is drawn by a pair; therefore, it is a private town-carriage, not a public cab. There is no cabman in the whole of London who would be so profligate as to use two horses where one will do.”

The Sergeant Warder cocked one ear toward the sound. “Hm-m-m. Dare say you’re right, your lordship. It do sound like a pair, now I listen closer. Still…”

“They are a well-trained pair,” said his lordship. “Almost perfectly in step. But since two hooves cannot possibly strike the paving stones at precisely the same instant, there is a slight echo effect, clearly discernible to the trained ear.”

The beeping sound of the whistle had stopped. Evidently the Warder at the gate had realized that the approaching vehicle was not a cab.

Nonetheless, the carriage could be heard to slow and stop outside the gate. After a moment, the reins snapped, and the horses started again. The carriage was turning, coming in the gate. It loomed suddenly out of the fog, seeming to coalesce into solidity out of the very substance of the rolling mist itself. It came to a halt at the curbing stone several yards away, still shadowy in the feeble yellow glow of the gas lamps.

Then a voice called out quite clearly from within it: “Lord Darcy! Is that you?”

It was plainly a feminine voice, and quite familiar, but because of the muffling effect of the fog and the distorting effect of the interior of the cab, Lord Darcy did not recognize it immediately. He knew that, standing almost directly under the gas lamp as he was, his own features stood out rather clearly at that distance.

“You have the advantage of me, my lady,” he said.

There was a low laugh. “You mean you can’t even read arms anymore?”

Lord Darcy had already noticed that a coat-of-arms was emblazoned on the door of the coach, but it was impossible to make it out in this light. There was no need to, however; Lord Darcy had recognized the voice upon the second hearing of it.

“Even the brilliancy of the arms of Cumberland can be dimmed beyond recognition in a London pea-soup,” Lord Darcy said as he walked toward the vehicle. “Your Grace should have more than just the regulation night-lights and fog-lights if you want your arms to be recognized on a night like this.”

He could see her clearly now; the beautiful face and the cloud of golden hair were only slightly dimmed by shadow and fog.

“I’m alone,” she said very softly.

“Hullo, Mary,” Lord Darcy said with equal softness. “What the deuce are you doing here?”

“Why, I came to fetch you, of course,” said Mary, Dowager Duchess of Cumberland. “You dismissed your cab earlier because you didn’t think about the fog coming, so now you’re marooned. There isn’t a cab to be had this side of St. Paul’s. Get in, my dear, and let’s leave this depressing prison.”

Lord Darcy turned toward the Sergeant Warder, who still stood beneath the gas lamp. “Thank you for your efforts, Sergeant. I shan’t need a cab. Her Grace has very kindly offered transportation.”

“Very good, your lordship. Good night, your lordship. Good night, Your Grace.”

They wished the Sergeant Warder a good night, Lord Darcy climbed into the carriage, and, at a word from Her Grace, the coachman snapped his reins and the carriage moved off into the swirling fog.

The Duchess pulled down the blinds and turned up the lamp in the top of the coach so that the two passengers could see each other clearly.

“You’re looking well, my dear,” she said.

“And you are as beautiful as ever,” Lord Darcy replied. There was a mocking glint in his eyes that Her Grace of Cumberland could not quite fathom. “Where would you like to go?” she asked, trying to probe that look with her own startlingly dark-blue eyes.

“Anywhere you’d like, my sweet. We could just drive about London for a while — for however long it takes you to tell me about the important information you have regarding this morning’s murder of Master Sir James Zwinge.”

Her eyes widened. For a moment, she said nothing. Then: “Damn! How did you know?”

“I deduced it.”

“Rot!”

“Not at all. You have a keen mind, my dear; you should be able to follow my reasoning.”

Again there was a silence, this time for nearly a minute, as Mary de Cumberland looked unblinkingly at Lord Darcy, her mind working rapidly. Then she gave her head a quick shake. “You have some information I don’t.”

“I think not. Unless, perhaps, I know how your mind works better than you do. You have the delightful habit, my dear, of making a man feel as though he were terribly important to you — even when you have to tell small lies to do it.”

She smiled. “You are important to me, darling. Furthermore, small lies are necessary to good manners and to diplomacy; there is no harm in them. And what, pray, does that have to do with your pretended deduction?”

“That was unworthy of you, my dear. You know I never pretend to mental abilities other than those I actually possess.” His voice had an edge.

She smiled contritely and put out a hand to touch his arm. “I know. I apologize. Please explain.”

Lord Darcy’s smile returned. He put his hand on hers. “Apology accepted. Explanation — a simple one — as follows:

“You claimed that you had come to fetch me at the Tower. Now, I know that, aside from myself, the Warders at the Tower, Master Sean, and two other people, no one in London knew of my whereabouts or could have learned it by other than thaumaturgical means. No one but those even knew I was in London. You are a sorceress, true, but only journeyman, and we both know you are not prescient to any degree above normal. You might have deduced that I would come immediately when I heard of Master Sean’s arrest, but you could not possibly have known at exactly what time I would leave the Tower. Ergo, your arrival was a coincidence.