She laid Badri's unresisting hand down at his side, typed something on the console, and went out.

Dunworthy sat down beside the bed and looked up at the screens. They looked the same, still indecipherable, the graphs and jags and generating numbers telling him nothing. He looked at Badri, who lay there looking battered, beaten. He patted his hand gently and stood up to go.

"It was the rats," Badri murmured.

"Badri?" Dunworthy said gently. "It's Mr. Dunworthy."

"Mr. Dunworthy…" Badri said, but he didn't open his eyes. "I'm dying, aren't I?"

He felt a twinge of fear. "No, of course not," he said heartily. "Where did you get that idea?"

"It's always fatal," Badri said.

"What is?"

Badri didn't answer. Dunworthy sat with him until the nurse came in, but he didn't say anything else.

"Mr. Dunworthy?" she said. "He needs to rest."

"I know." He walked to the door and then looked back at Badri, lying in the bed. He opened the door.

"It killed them all," Badri said. "Half of Europe."

Colin was standing at the registrar's desk when he came back down, telling her about his Christmas gifts. "My mother's gifts didn't arrive because of the quarantine. The postman wouldn't let them through."

Dunworthy told the registrar about the T-cell enhancement and she nodded and said, "It will just be a moment."

They sat down to wait. It killed them all, Dunworthy thought. Half of Europe.

"I didn't get to read her her motto," Colin said. "Would you like to hear it?" He didn't wait for an answer. "Where was Father Christmas when the lights went out?" He waited expectantly.

Dunworthy shook his head.

"In the dark."

He took his gobstopper out of his pocket, unwrapped it, and stuck it in his mouth. "You're worried about your girl, aren't you?"

"Yes."

He folded up the gobstopper wrapper into a tiny packet. "What I don't understand is, why can't you go get her?"

"She isn't there. We must wait for the rendezvous."

"No, I mean why can't you go back to the same time you sent her through and get her while she was still there? Before anything happened? I mean you can go to any time you want, can't you?"

"No," he said. "You can send an historian to any time, but once she's there, the net can only operate in real time. Did you study the paradoxes at school?"

"Yes," Colin said, but he sounded uncertain. "They're like time-travel rules?"

"The space-time continuum doesn't allow paradoxes," Dunworthy said. "It would be a paradox if Kivrin made something happen that hadn't happened, or if she caused an anachronism."

Colin was still looking uncertain.

"One of the paradoxes is that no one can be in two places at the same time. She's already been in the past for four days. There's nothing we can do to change that. It's already happened."

"Then how does she get back?"

"When she went through, the tech took what's called a fix. It tells the tech exactly where she is, and it acts as a…um…" he groped for an understandable word. "A tether. It ties the two times together so the net can be reopened at a certain time, and she can be picked up."

"Like, 'I'll meet you at the church at half-past six?'"

"Exactly. It's called a rendezvous. Kivrin's is in two weeks. The twenty-eighth of December. On that day the tech will open the net, and Kivrin will come back through."

"I thought you said it was the same time there. How can the twenty-eighth be two weeks from now?"

"They used a different calendar in the Middle Ages. It's December the seventeenth there. Our rendezvous date is the sixth of January." If she's there. If I can find a tech to open the net.

Colin pulled out his gobstopper and looked at it thoughtfully. It was a mottled bluish-white and looked rather like a map of the moon. He stuck it back in his mouth.

"So, if I went to 1320 on the twenty-sixth of December, I could have Christmas twice."

"Yes, I suppose so."

"Apocalyptic," he said. He unfolded the gobstopper wrapper and folded it into an even tinier packet. "I think they've forgotten about you, don't you?"

"It's beginning to look that way," Dunworthy said. The next time a house officer came through, Dunworthy stopped him and told him he was waiting for T-cell enhancement.

"Oh?" he said, looking surprised. "I'll try to find out about it." He disappeared into Casualties.

They waited some more. "It was the rats," Badri had said. And that first night he had asked Dunworthy, "What year is it?" But he had said there was minimal slippage. He had said the apprentice's calculations were correct.

Colin took his gobstopper out and examined it several times for change in color. "If something terrible happened, couldn't you break the rules?" he said, squinting at it. "If she got her arm cut off or she died or a bomb blew her up or something?"

"They're not rules, Colin. They're scientific laws. We couldn't break them if we tried. If we attempted to reverse events that had already happened, the net wouldn't open."

Colin spit his gobstopper into the wrapper and folded the wrinkled paper carefully around it. "I'm sure your girl's all right," he said.

He jammed the wrapped gobstopper in his jacket pocket and pulled out a lumpy parcel. "I forgot to give Great-Aunt Mary her Christmas present," he said.

He jumped up and started into Casualties before Dunworthy could caution him to wait, got opposite the door, and came tearing back.

"Blood! The Gallstone's here!" he said. "She's coming this way."

Dunworthy stood up. "That's all that's needed."

"This way," Colin said. "I came in the back door the night I got here." He sprinted off in the other direction. "Come on!"

Dunworthy could not manage a sprint, but he walked quickly down the labyrinth of corridors Colin indicated and out a service entrance into a side street. A man in a sandwich board was standing outside the door in the rain. The sandwich board said, "The doom we feared is upon us," which seemed oddly fitting.

"I'll make certain she didn't see us," Colin said, and dashed around to the front.

The man handed Dunworthy a flyer. "THE END OF TIME IS NEAR!" it said in fiery capital letters. "'Fear God, for the hour of his judgment is come.' Rev. 14:7."

Colin waved to Dunworthy from the corner. "It's all right," Colin said, slightly out of breath. "She's inside shouting at the registrar."

Dunworthy handed the flyer back to the man and followed Colin. He led the way along the side street to Woodstock Road. Dunworthy looked anxiously toward the door of Casualties, but he couldn't see anyone, not even the anti-EC picketers.

Colin sprinted another block, and then slowed to a walk. He pulled the packet of soap tablets out of his pocket and offered Dunworthy one.

He declined.

Colin popped a pink one in his mouth and said, none too clearly, "This is the best Christmas I've ever had."

Dunworthy pondered that sentiment for several blocks. The carillon was massacring, "In the Bleak Midwinter," which also seemed fitting, and the streets were still deserted, but as they turned down the Broad, a familiar figure hurried toward them, hunched against the rain.

"It's Mr. Finch," Colin said.

"Good Lord," Dunworthy said. "What do you suppose we've run out of now?"

"I hope it's Brussels sprouts."

Finch had looked up at the sound of their voices. "There you are, Mr. Dunworthy. Thank goodness. I've been looking for you everywhere."

"What is it?" Dunworthy said. "I told Ms. Taylor I'd see about a practice room."

"It isn't that, sir. It's the detainees. Two of them are down with the virus."

21 December 1320 (Old Style.) Father Roche doesn't know where the drop is. I made him take me to the place where Gawyn met him, but even standing in the clearing didn't jog my memory. It's obvious Gawyn didn't happen upon him until he was a long way from the drop, and by that time I was completely delirious.