He wouldn’t tell anyone about her sneaking into the lab, not until he’d had more time to think about it. Was this why James had been drawn to Grace? But James wasn’t interested in experiments and science—not the way Grace seemed to be. She’d been so eager to look through the microscope at the gunpowder compounds he’d been studying; so curious to see the contents of his journals.

But it was silly to dwell on it. Grace would likely never visit the lab again. It was too bad—many great discoveries had been made by teams working in tandem. Look at the Curies, who had just won the Nobel Prize for their experiments with radiation. Perhaps if he told her about the Curies…

Christopher’s thoughts were interrupted by a banging at the front entrance. He hurried upstairs to answer it; the rest of the household must have gone to bed hours ago. He opened the door to find Matthew waiting on the stoop. He was bundled in a red wool coat, hatless and blowing on his hands for warmth.

Christopher blinked in surprise. “Why are you knocking on the door to your own house?”

Matthew rolled his eyes. “I think they’ve changed the locks. My mother, making a point as usual.”

“Oh. Well, do you want to come in?”

“No need; I’m just on an errand. James sent me. You still have that pithos, don’t you?”

“I do!” Christopher said, brightening. Excitedly he explained the discovery that the stele removed runes from one person and transferred them to another. Though—for reasons he couldn’t entirely explain—he left Grace out of it. “I must say, I find it very strange,” he concluded. “And inefficient! But the killer must be murdering people and taking their runes for some dark purpose that we do not yet grasp.”

“Right, I see,” Matthew said, though Christopher wasn’t sure he did see, as he hadn’t appeared to be paying attention. “Whatever its purpose, James needs it right away—so I had best take it to him now.”

Of course James would already have a plan of some kind—James was always coming up with plans. Christopher felt around in his pockets and located one of the white rags he used for cleaning his instruments. He carefully wrapped the pithos in it and handed it to Matthew.

“It’s just as well you take it,” he said. “I’m completely exhausted anyway. I’m going to sleep in your room, if you don’t mind, seeing as you’ve got a whole other flat.”

“Of course,” Matthew said, tucking the pithos into a pocket inside his coat. “My home is yours.”