She looked fondly at Cyril. “When we’ve got Tossie safely connected to Mr. C,” she said, scratching behind his ears, “I think I’ll take you back with me.”

She looked up at me impishly. “I’m kidding,” she said. “I’ve sworn off incongruities. I would like to have a bulldog, though.”

“Me, too,” I said.

She ducked her head. “They haven’t got Carruthers out yet,” she said. “The net still won’t open. Warder thinks perhaps it’s a temporary blockage. She’s switched to an accelerated four-hour intermittent to try and get past it.”

“Has T.J. solved the mystery of why the incongruity was able to get past the net’s defenses?” I asked.

“No. He’s figured out why Napoleon lost the battle of Waterloo, though.” She grinned, and then said more seriously, “And he was finally able to generate an incongruity.”

“An incongruity?” I said. “Why didn’t you tell me?”

“It was only a simulated incongruity. And it’s not the right sort. It occurred as part of a self-correction. It was one of those sims where he had an historian kill Wellington. When he introduced a second historian into the sim, the historian was able to steal the rifle that the first historian was going to shoot Wellington with and bring it forward through the net, so that it prevented an incongruity rather than causing one. But he said to tell you that at least it proves bringing something forward through the net is theoretically possible, even if it didn’t apply to our case.”

Theoretically possible. It still didn’t solve the problem of getting the net open to get the first historian through to kill Wellington in the first place.

“Anything else?” I asked.

“No. He and Mr. Dunworthy were happy that we’d managed to persuade Tossie to go to Coventry. They both think the fact that they haven’t been able to find any increased slippage around the original drop means the incongruity was short-term and that all it needs to correct itself is for us to get her to St. Michael’s on time.”

She ducked her head again. “And, if it does, we’ll be done here and have to go face Lady Schrapnell. And I promised I’d help you find the bishop’s bird stump. So I decided to wait for you.”

She shifted Cyril off her lap and pulled a pen, a bottle of ink, and some sheets of paper out of her pocket and set them on the hay.

“What’s all that for?” I asked.

“For making a list of all the possibilities of what might have happened to the bishop’s bird stump. Lord Peter Wimsey and Harriet Vane made a list in Have His Carcase.”

“There’s no such thing as listing all the possibilities,” I said. “The continuum’s a chaotic system, remember?”

She ignored me. “In an Agatha Christie mystery, there’s always one possibility you haven’t considered, and that’s the solution to the mystery. All right,” she said, dipping her pen in the ink. “One, the bishop’s bird stump was in the cathedral during the raid and was destroyed in the fire. Two, it was in the cathedral, survived the fire, and was found in the rubble. Three,” she said, writing busily, “it was rescued during the raid.”

I shook my head. “The only things saved were a flag, two sets of candlesticks, a wooden crucifix, and the altar books. There’s a list.”

“We are writing down all the possibilities,” she said. “Later, we’ll eliminate the ones that are impossible.”

Which so far was all three.

“Four,” she said, “it survived the raid, even though it didn’t make the list for some reason, and it’s stored somewhere.”

“No,” I said. “Mrs. Bittner went through all the things in the cathedral when they sold it, and it wasn’t there.”

“Lord Peter didn’t keep contradicting Harriet when she was making a list,” she said. “Five, it wasn’t in the church during the raid. It was removed sometime between the tenth and the fourteenth of November.”

“Why?” I said.

“For safekeeping. With the east windows.”

I shook my head. “I went to Lucy Hampton rectory to see. The only things they had of Coventry’s were the windows.”

“Oh. Well, what if some member of the congregation took the bishop’s bird stump home for safekeeping? Or to polish it or something, so that it just happened to be out of the cathedral that night?”

“If that happened, why didn’t the person bring it back?”

“I don’t know,” she said, biting her lip. “Perhaps he was killed during the raid, by a high-explosive bomb, and whoever inherited it didn’t know it belonged to the cathedral.”

“Or he could have thought to himself, ‘I can’t do this to the people of Coventry. They’re already going to have to suffer the loss of their cathedral. I can’t inflict the bishop’s bird stump on them as well.’ ”

“Be serious,” she said. “What if he didn’t bring it back because it was destroyed in the raid, by a bomb or something.”

I shook my head. “Even a high-explosive bomb couldn’t destroy the bishop’s bird stump.”

She flung the pen down. “I am so glad we’re going to Coventry today so I can actually see the bishop’s bird stump. It cannot possibly be as bad as you say.”

She looked thoughtful. “What if the bishop’s bird stump was involved in a crime? It was used as a murder weapon, and it got blood on it, so they stole it to keep anyone from finding out about the murder.”

“You have been reading too many murder mysteries,” I said.

She dipped her pen in the ink again. “What if it was stored in the cathedral, but inside something else, like Poe’s ‘The Purloined Letter’?” She started to write and then stopped and frowned at the pen. She pulled an orange dahlia penwiper out of her pocket.

“What are you doing?” I said.

“Wiping my pen,” she said. She stuck the pen into the dahlia and wiped it off between the layers of cloth.

“It’s a penwiper,” I said. “A pen wiper! It’s used to wipe pens!”

“Yes,” she said, looking at me dubiously. “There was ink on the point. It would have blotted the paper.”

“Of course! So you wipe it on a penwiper!”

“How many drops have you had, Ned?” she said.

“You’re a wonderful girl, you know that?” I said, grabbing her by the shoulders. “You’ve solved a mystery that’s been plaguing me since 1940. I could kiss—”

There was a bloodcurdling scream from the direction of the house, and Cyril buried his face in his paws.

“What now?” Verity said, looking disappointed.

I let go of her shoulders. “The daily swoon?”

She stood up and began brushing straw off her skirts. “This had better not be anything that keeps us from going to Coventry,” she said. “You go first. I’ll come in through the kitchen.”

“Mesiel!” Mrs. Mering shrieked. “O, Mesiel!”

I took off for the house, expecting to find Mrs. Mering laid out among the bric-a-brac, but she wasn’t. She was standing halfway down the stairs in her wrapper, clutching the railing. Her hair was in two operatic braids, and she was waving an empty velvet-lined box.

“My rubies!” she was wailing to the Colonel, who had apparently just come out of the breakfast room. He still had his napkin in his hand. “They’ve been stolen!”

“I knew it!” the Colonel, shocked into using a subject, said. “Should never have allowed that medium person in the house!” He threw down the napkin. “Thieves!”

“O, Mesiel,” Mrs. Mering said, pressing the jewel case to her bosom, “surely you don’t think Madame Iritosky had anything to do with this!”

Tossie appeared. “What’s happened, Mama?”

“Tocelyn, go and see whether any of your jewelry is missing!”

“My diary!” Tossie cried and scampered off, nearly colliding with Verity, who must have come up the back stairs.

“What is it?” Verity said. “What’s happened?”

“Robbed!” the Colonel said succinctly. “Tell Madame Whatever-Her-Name-Is and that Count person to come down immediately!”

“They’ve gone,” Verity said.

“Gone?” Mrs. Mering gasped, and I thought she was going to pitch over the stairs.