Probably, I thought, the way this night is going.

“No,” I said. “Thank you. Good night, Baine. Get some rest. And don’t worry. Princess Arjumand’s home safe and sound, and no harm done.” I hope.

“Yes, sir,” he said. “Good night, sir.”

I opened the door to let him out and held it open a crack to watch him till he reached the door to the servants’ quarters and went through it, and then went over to the wardrobe and knocked quietly.

There was no answer.

“Verity?” I said, and pulled the double doors open. Verity was sitting huddled in the wardrobe, her knees hunched against her chest. “Verity?”

She looked up at me. “He wasn’t going to drown her,” she said. “Mr. Dunworthy said I should have thought before I acted. He would have come back and rescued her if I hadn’t interfered.”

“But that’s good news,” I said. “It means she wasn’t a nonsignificant event, and my returning her didn’t create an incongruity.”

She nodded, but without conviction. “Perhaps. But if Baine had rescued her, she wouldn’t have been missing for four days. They wouldn’t have gone to Madame Iritosky’s, and Tossie would never have met Terence.” She scrambled out of the wardrobe. “I’ve got to tell Mr. Dunworthy this.” She started for the door. “I’ll be back as soon as I can and tell you what I find out.”

She put her hand on the door. “I won’t knock,” she whispered. “If Mrs. Mering hears knocking, she’s liable to think it’s spirits rapping. I’ll scratch on the door, like this.” She demonstrated. “I’ll be back soon,” she said, and opened the door.

“Wait,” I said, and retrieved Mrs. Mering’s boot from under the mattress. “Here,” I said, thrusting it at Verity. “Set this in front of Mrs. Mering’s door.”

She took the boot. “I won’t even ask,” she said, grinned, and slid out the door.

I didn’t hear any statuary crashes, or cries of, “The spirits!” from Mrs. Mering’s room, and after a minute I sat down in the chair to wait. And worry.

I wasn’t supposed to have brought the cat through. I remembered now Mr. Dunworthy saying, “Stay right there!” but I had thought he meant not to leave the net.

And it wouldn’t be the first time a miscommunication had affected history. Look at the countless times when a message which had been misunderstood or failed to get through or fallen into the wrong hands had changed the outcome of a battle: Lee’s accidentally dropped plans for Antietam, and the Zimmerman telegram, and Napoleon’s illegible orders to General Ney at Waterloo.

I wished I could think of an instance in which a failure to communicate had had anything but disastrous results. I wasn’t sure there were any. Look at Hitler’s migraine on D-Day. And the Charge of the Light Brigade.

Lord Raglan, standing on a hill, saw the Russians trying to retreat with captured Turkish artillery and ordered Lord Lucan to stop them. Lord Lucan, not on a hill and possibly suffering from Difficulty in Distinguishing Sounds, didn’t catch the word “Turkish,” couldn’t see any artillery except the Russian cannons pointed straight at him, and ordered Lord Cardigan and his men to charge straight at them. With predictable results.

“Into the Valley of Death rode the six hundred,” I murmured, and heard a faint scratching on the door.

I didn’t see how it could possibly be Verity. She’d scarcely been gone long enough to make it out to the gazebo and back, let alone to the future.

“Who is it?” I whispered through the door.

“Verity,” she whispered back.

“I told you I’d scratch on the door,” she said when I let her in. She had a brown paper parcel under her arm.

“I know,” I said, “but you were only gone five minutes.”

“Good,” she said. “That means there wasn’t any slippage, which is a good sign.” She sat down on the bed, looking pleased with herself. The news must be good.

“What did Mr. Dunworthy say?” I asked.

“He wasn’t there,” she said happily. “He’d gone up to Coventry to see Elizabeth Bittner.”

“Mrs. Bittner? The wife of the last bishop of Coventry?”

She nodded. “Only he didn’t go to see her in her capacity as bishop’s wife. She apparently worked on the net back in the early days. Do you know her?” she asked curiously.

“Lady Schrapnell had me interview her about the bishop’s bird stump.”

“Did she know where it was?”

“No.”

“Oh. Can I eat your biscuits?” she said, looking hungrily at the tray on the nightstand. “I’m starving.” She picked one up and took a bite out of it.

“How long were you there?” I asked.

“Hours,” she said. “Warder wouldn’t tell me where T.J. was — he was hiding from Lady Schrapnell, and he’d told Warder not to tell anyone where he was. It took me forever to track him down.”

“Did you ask him about my making Terence miss meeting Maud?”

“Yes,” she said. “Can I have your cocoa?”

“Yes. What did he say?”

“He said he thinks it’s unlikely that Terence was supposed to have met Maud, or if he was, that the meeting was nonsignificant, because if it had been, the net wouldn’t have opened.”

“But if my bringing the cat through caused an incongruity?” I said.

She shook her head. “T.J. doesn’t think it did. He thinks I caused it.”

“Because of what Baine told us.”

She nodded. “That, and the excessive slippage.”

“But I thought that was supposed to be due to Coventry’s being a crisis point.”

She shook her head. “Not the area of slippage in Coventry. The one in Oxford. In April of 2018.”

“2018? What crisis point is that?”

“It’s not, to anyone’s knowledge,” she said. “That’s why Mr. Dunworthy went to see Mrs. Bittner, to see if she remembers anything unusual about the drops or the time travel research they did that year that might account for it, but neither of them could remember anything. So if I caused the incongruity, then your bringing the cat back wouldn’t have. It would have been correcting it, and so it should have made things better, not worse. And having Terence miss meeting someone would hardly make things better, especially if meeting them might have kept him from getting to Iffley in time to see Tossie. Which means Terence must not have been supposed to meet Maud, and we don’t have to worry about it being a symptom the incongruity’s getting worse.”

“A symptom? What do you mean?”

“According to Fujisaki, the first line of defense is excessive slippage. Then, if that fails to correct the incongruity, there’s an increase in coincidental happenings, and if that fails, then discrepancies appear.”

“Discrepancies? You mean the course of history begins to alter?”

“Not at first. But the incongruity makes it destabilize. The way T.J. explained it was, that instead of there being a single fixed course of events, there becomes a superposition of probabilities.”

“Like in Schrodinger’s box,” I said, thinking of the famous thought experiment with the Geiger counter and the bottle of cyanide gas. And the cat.

“Exactly,” Verity said happily. “The course of events that will happen if the incongruity’s corrected, and if it’s not, both exist side by side, sort of. When the self-correction’s completed, they collapse into one course of events or the other. But until that happens, there may be discrepancies between the observed and recorded events. Only the only record we have is Tossie’s diary, and we can’t read that, so there’s no way to tell whether Terence and Maud’s not meeting is a discrepancy or not.”

She bit into another biscuit. “That’s why I was gone so long. After I talked to T.J., I went over to the Bodleian to start a search on Terence and then over to Oriel to ask the forensics expert to look for references to him in the diary and to see if she’d found out Mr. C’s name.”

“And had she?” I said, thinking perhaps this was why Verity seemed so happy.

“No. She’d recovered one entire passage, which unfortunately was a description of a dress Tossie was having made. Four paragraphs of pintucks, Brussels lace, French embroidery, openwork insets, and—”