A Conspiracy in Belgravia (Lady Sherlock #2)

She nodded coolly. “My lord.”

Over the years they had come to a domestic arrangement that enabled them to spend as much time apart as possible, while still ostensibly living as man and wife. They took their meals separately, simple enough when she had her morning cocoa in bed and he availed himself of luncheons at his clubs. And during the Season it was particularly easy to avoid each other at dinner: Whether they dined out or hosted dinner parties at home, it was Society’s unspoken rule that such occasions were not for chitchat between husband and wife, but socializing with others.

With regard to the children, too, they had come to an unspoken agreement: He breakfasted with them on weekdays and took them out Sunday afternoons; she lunched with them on weekdays and had the nursery to herself Sunday evenings.

She would have tucked the children in bed just now—had she managed the feat five minutes sooner, as she usually did, they would not have run into each other. Come to think of it, she had also been late coming back home this afternoon. He didn’t mind spending more time with his children, but it was uncharacteristic of her to be less than punctual.

She descended past him, her steps impatient.

“Did you use the typewriter in the study, by the way?”

He did not say my typewriter or my study. But she must have heard something to that effect. She turned around. “Would you like me not to, in the future?”

“You are at perfect liberty to avail yourself of anything in this house. I was only curious—you do not ordinarily require a typewriter.”

“Sometimes I wish for my correspondence to be typewritten,” she said, her tone civil but distant.

He wasn’t sure what had led him to ask the question in the first place. Something about his wife felt different of late. Charlotte Holmes would be able to tell him exactly what constituted that disparity; he, not blessed with Sherlockian faculties of observation, had to rely on his gut, which didn’t tell him how or why, but only that he should pay attention.

Was it possible she was having an affair? He had yet to betray his marriage vows; he didn’t think she had either. Not to mention that for a while now, he’d had the impression that romantic entanglement was the last thing she was after.

But did it behoove him to be more watchful, in case she gave him grounds for divorce? Would he actually put those grounds to use? Was he hardened enough to tear his children from their mother, who, despite her flaws as a wife, had always been a caring parent?

And if he was never going to divorce her, what would he gain by finding out whether she might be having an affair?

“I wish you a good evening, Lady Ingram,” he said.



Charlotte walked into her room, shut the door, and leaned back against it, a hand over her face.

It had been a long, strange day, from Lord Bancroft’s proposal to Mr. Finch’s nondisappearance. And to think, only a little more than twenty-four hours ago, she had kissed Lord Ingram. Very briefly, to be sure, but the first time in more than a decade, a moment of stark, all-engrossing heat.

Events were easy to deal with. Emotional responses, less so. They were not crisp or factual. They mutated at will. They expanded to fill all available space in one’s consciousness and left no room for anything else.

And no clarity with which to think.

The situation with Mr. Finch was too incongruous to be normal. But between Lady Ingram’s anguish, Mrs. Watson’s distress, and her own discomfort with having Lady Ingram as a client, Charlotte couldn’t pin down exactly what was bothering her.

It was as if she were trying to listen to someone timidly tapping out a message in Morse code on the window, in the midst of a hailstorm.

She pushed away from the door. The dossier from Lord Bancroft lay on her bed. She pulled out the next envelope.

A cipher: a page of uppercase letters with no breaks.

The clue informed her that it was a Vigenère cipher. Vigenère ciphers had been in use for centuries but were first solved only a generation ago. Mr. Charles Babbage, who managed the groundbreaking feat, did not publish his methods. But Charlotte, with a mind in search of use and a great deal of time, had made Livia compose several Vigenère ciphers, so she could learn how to decode them on her own.

And what she learned was that solving Vigenère ciphers was an experience best compared to being kicked in the head by a distempered mule. Repeatedly—because not only was it brain-crackingly difficult, but the long, drawn-out process could not be made shorter or less tedious.

Lord Bancroft believed this to be the kind of mental exertion that would give her pleasure?

To be fair, before she knew exactly what solving Vigenère ciphers entailed, she had thought so, too.

At least now she knew that Lord Bancroft had instructed his underling to select difficult cases for her—and that most certainly counted as a point in his favor.



A Caesar cipher, despite its majestic name, was a simple one, in which each letter of the plaintext was replaced by another letter a fixed number of positions up or down the alphabet. In a Caesar cipher with a right shift of 2, for example, A was replaced by C, B by D, and so on.

The Vigenère cipher incorporated the principle of Caesar ciphers. First, Charlotte constructed a tabula recta, a twenty-six-by-twenty-six square that represented all possible letter-to-letter substitution schemes.



If she were writing the cipher, this would be the point at which she chose a keyword.

To encode the sentence CHARLOTTE IS SHERLOCK, with the keyword HOLMES, she would write the following:


CHARLOTTEISSHERLOCK

HOLMESHOLMESHOLMESH

In coding the first letter C, one consulted column C, row H of the tabula recta. The next letter was to be found at the intersection of column H, row O. The process was repeated as many times as there were letters in the original message. In the end, the cipher text would read:


JVLDPGAHPUWKOSCXSUR

But since someone else had chosen the keyword for this cipher, Charlotte must first find out what it was. She examined the huddle of letters that formed the cipher text, looked for repeated sequences, and counted the number of letters between each iteration of the same sequence—to help determine the length of the keyword.

By the stroke of midnight, her temples throbbed. Mr. Babbage, in fact, had turned down the opportunity to decipher King Charles I’s coded letters—probably because his head still ached from the Vigenère ciphers.

She rose and walked to the window. Almost immediately she saw Lord Ingram in her mind’s eye. Winter, two months after his wedding, at a house party in the country. She had come upon him outside, on a snow-and mistletoe-draped terrace. He had been smoking, his head tilted back, blowing a leisurely stream of smoke into the air.