“Only too glad, Mrs. Holloway. Is this flat not astonishing? A far cry from my two cramped rooms in Bloomsbury. So much more than a scholar can expect, but my benefactor is proving generous.”

He babbled the words as he pumped my hand, avoiding looking at Cynthia.

“I am glad to hear it, Mr. Thanos,” I said as he finally released me. I believed he deserved a mansion, one in proportion with his vast cleverness.

“Of course, I have not yet begun my lectures, and perhaps when the students fall asleep or throw things at me, he might change his mind.”

Mr. Thanos laughed breathily, and I smiled in response, though I doubted he need worry.

“What will you lecture on?” I asked politely. Mathematics, I was certain, or an obscure puzzle in science I would not understand.

“Maxwell’s demon,” Mr. Thanos answered. “No one can solve the problem, including me, though I have some ideas. But perhaps I can inspire the next great genius to do so.”

“Demons?” Mr. Fielding’s voice sounded behind me. “I would have thought that my field of expertise.”

He kept his tone light, but when I turned to him, I saw that Mr. Fielding’s face was drawn, the usual roguish look in his eyes absent. His lips were colorless, his stance rigid.

“No, no,” Mr. Thanos said quickly. “Not a real demon, you understand. A thought experiment. To do with thermodynamics. You see there is a box, with two compartments and a little door—”

“It will keep.” Daniel broke through his words. “Another time.”

Mr. Thanos looked sheepish. “Ah yes. Of course. My apologies. I find it fascinating, is all.”

“You can explain it to me later,” Cynthia said, taking his arm and leading him toward the fire. “I’m interested in all this mathematical thinking.”

Mr. Fielding watched them go, but where he once might have made a quip, today, he only looked sad. I touched his arm.

“Are you well, Mr. Fielding?”

“Not really.” Behind the sorrow in his eyes lay vast fury. “But I will carry on. What else can I do?”

I caught Daniel’s glance, and he shook his head, looking grim. It must have been no easy task breaking the news of Nurse Betts’s death to Mr. Fielding.

“Miss Townsend might turn up,” Cynthia said as she allowed Mr. Thanos to usher her to a chair. “She is interested in our problem and would like to help. She knows ever so many people.”

“The more the merrier,” Mr. Fielding said. He indicated a chair for me, a plush one that was more fitting for a lady than a cook, and hovered next to me until I sat in it. “Anything that will help me find the bastard who did over my Nell.”

“We will find him.” I tried to sound confident.

“And when we do,” Mr. Fielding told Daniel in a hard voice, “I get him.”