“To what?” Anne asked.

“To do something that requires all those things,” Emily said. “So I suppose I am looking for some trace, some physical remnant from the moment the bones were placed here that will tell us something.”

“There are a great many dead birds here in the grate,” Anne told Emily as she examined the chimney breast once again. “Five or six crow skulls, and the bones of smaller birds too.”

“That would indicate that the birds were attracted to the chimney by the promise of carrion,” Emily said, ever blunt. “Therefore we can assume the body was not skeletal when it was placed here.”

“Excellent,” Anne said, taking in another deep breath of cold air. Would that she could detach herself from the humanity and tragedy of the bones in the way that Emily could. It wasn’t that her sister didn’t care as much—Anne was certain that she did. It was just that Emily was able to unravel the most complicated weave into separate strands of colour, all the better to see how it had been made in the first place.

“Detecting does seem to involve a great deal of time looking for something that might not exist,” Anne said, but Emily, absorbed as she was in studying every inch of every surface of a torn-out stone, did not reply.

Anne joined Emily on the filthy floor and, after several moments of silent work, stopped and stared for a long moment at what she had discovered, for it was almost certainly the strange and unusual thing that Emily had been looking for.

Clearly etched into the blackened surface of the stones were purposeful marks, not forming any letter or design Anne recognised, but rather something like the Egyptian hieroglyphs that had confounded historians until only a few decades earlier with the discovery of the Rosetta stone. As unlikely as it was that Egyptian writings should appear on the inside of a chimney breast in an isolated Yorkshire house, it was no more unlikely than any other explanation for the strange etchings.

“Emily,” Anne said, offering forth her treasure, “these markings are unusual.”

“Yes!” Emily said, taking the stone in her hand. “Yes, there is no mistaking that those are deliberate marks, is there? Well done, Anne—let us see if we may find any more and perhaps make sense of this fragment. It may well unlock the whole affair!”

After finding the first marked stone, other finds followed apace, perhaps because they had been placed side by side in the chimney breast wall, Anne considered, or perhaps because now Emily and she knew what they were looking for. As the morning dwindled away outside the shattered window, Anne and Emily sorted a small pile of similarly marked stones, thirteen in total.