A Conspiracy in Belgravia (Lady Sherlock #2)

“If you will excuse me, ladies. There is something I must attend to.” She barely remembered to shake Madame and Mademoiselle de Blois’s hands, before pivoting around for Mrs. Watson’s house.

In her room, she took out the deciphered text again. What was it that kept scratching at the back of her head? Ah yes, the words as the hawk flies. If the author wished to convey that the place was a thousand yards distant in a straight line, then why not say as the arrow flies? Or as the crow flies, since hawks wheeled and circled, but crows were said to take the shortest path?

Not to mention, no one measured distances in thousands of yards.

The noticeable lack of O’s came to mind—instead of constituting around seven point five percent of the letters, the O’s in this passage accounted for just under three percent. What if hawk had been selected because the writer of the message hadn’t wished to put a word that contained the letter O at that particular point in the passage?

She picked up a pen and underlined all sixteen of the O’s. They seemed most heavily clustered around the middle of the passage. But if there was a significance to the pattern of their distribution, it wasn’t obvious. She stared at the passage for several more minutes, then took a blank sheet of paper and copied the text, but this time all in lowercase.

Sometimes a different perspective helped. Not this time.

She tried various methods—it wasn’t as easy to hide a hidden message in plaintext, but it could be done. She examined the cross bars on the t’s and the dots on the i’s to see whether they formed legible Morse code. They didn’t. She looked at the punctuation marks she had added and varied them to see if they signaled anything. They signaled nothing.

She got up and walked about the room. When that failed to trigger any fresh perspective, she went down to the kitchen. Madame Gascoigne was pulling a batch of madeleines from the oven—a treat for the ladies when they returned from their walk.

Charlotte absconded with half a dozen of the madeleines. She sat down at her desk and examined the plaintext message again, stuffing the first still-hot madeleine into her mouth. As the little cake disappeared into her stomach, her brain suddenly . . . sprouted.

Of course. Now she saw the error of her ways. She had been so consumed by the Vigenère cipher that she—horrors—hadn’t been eating properly. A quick glance at the mirror told her that she was down to only one point three chins. No wonder her brain was so slow and unwieldy, like a steam engine on the last shovel of coal.

Two more madeleines and she felt like a new woman.

The O’s. What if they weren’t letters? What if they were instead numbers?

Zeroes.

And if they were zeroes, that would make the I’s or the L’s ones.

According to her notes, I’s were overrepresented, acceptable given that the other vowels must compensate for the shortage of O’s. But L’s, like O’s, were underrepresented. And when she thought about the distance measured in thousands of yards . . . What if the cipher writer had been trying to avoid more reasonable units such as miles or furlongs, which would have put an L where it did not belong?

She made a fresh copy of the plaintext and underlined all the L’s and the O’s.


Much that remained in the ancient valley had been ransacked by raiders in later centuries. The ruins were a sad sight, decrepitude sans grandeur, an insipid past that inspired little beyond a gloomy sigh. We were glad as we departed, leaving behind the mounds of rubble and that general air of mournfulness. Onward! Lucky for us, our next destination, a thousand yards eastward as the hawk flies, was as magnificent as this one was inferior. The granite edifice must have been a palace in its heyday and the treasures within must have been astonishing. My friend, pray excuse my brevity. Let me dig instead and write again when I have unearthed artefacts and other archaic gems.

The L’s and O’s, once converted into ones and zeroes, respectively, made a string of numbers thirty-one digits long: 1111101001100110010100001001010

She translated it into Morse code, dashes for ones and dots for zeroes. But no matter how she parsed the resultant sequence of dots and dashes, they refused to make any sense. And if they, too, were a code, then she didn’t have a long enough sequence for decoding.

Deciphering, a science and art only for those with no fear of ending up in any number of blind alleys.

She nibbled on the next madeleine, hoping this wouldn’t turn out to be a six-madeleine problem, because she had hopes of stowing away the last two for a late-night snack. But what else was she to do with a passel of ones and zeroes?

She stopped midchew. Ones and zeroes, when used in a binary system, could convey other numbers. The calculation might be a bit tricky. To convert a thirty-one-digit binary number, she would need to calculate powers of two up to the thirtieth, which promised to be a sizable number. Nevertheless, it would be much, much easier than cracking a Vigenère code—orders of magnitude easier.

But what purpose would the resultant number serve?

She could take out any passage from any book or newspaper, underline the L’s and the O’s, turn them into ones and zeroes, and arrive at a binary number.

Her gaze went around the room and landed on an item she had recently bought, a well-made object at once beautiful and very, very useful.

Hmm. She might just know what to do if she had two numbers.





Eight





As Lord Ingram Ashburton’s hansom cab approached Mrs. Watson’s house, his attention was ensnared by the middle-aged nanny pushing a perambulator.

A nanny out and about in these parts was a perfectly common sight. Mrs. Watson’s house faced a large, verdant park. At any point during the day there could be nurses, nannies, and governesses taking their charges for some fresh air. The thing was, he was almost entirely sure that this particular nanny had been selling cigarettes and boutonnieres two days ago, when he last passed before the house—but did not, in the end, choose to ring the doorbell.

He didn’t ring this time either.

Before his vehicle had come to a full stop, Charlotte Holmes, clad in a burgundy-and-cream-striped dress, stepped out of the front door, a cream parasol in one gloved hand, a burgundy handbag in the other, the whole ensemble capped off by a toque festooned with jaunty burgundy feathers.

On another woman, this would have been dramatic. On Holmes, it passed for austere—he was far more accustomed to seeing her in sartorial concoctions that featured endless yards of laces, fringes, and ruffles, a mobile ribbon stand of a woman.

“May I offer you the use of a conveyance, miss?” he said.

She couldn’t possibly have been expecting him, but judging by her perfectly composed expression, one would have had reason to conclude that he stopped before Mrs. Watson’s house at this hour every day to present the use of a for-hire carriage. “Thank you, sir. You may indeed.”