She looked unconvinced, but she punched up a code, laid the receiver in its cradle, and said, "You don't mind if I work while we talk?"

"No," Dunworthy said, relieved. "Please do."

She moved abruptly out-of-picture, returned, and punched up something else. "Sorry. It won't reach," she said, and the screen went fuzzy while she, presumably, moved the phone to her new worksite. When the picture reappeared, Montoya was crouched in a mudhole by a stone tomb. Dunworthy supposed it to be the one the lid of which she and Badri had nearly dropped.

The lid, which bore the effigy of a knight in full armor, his arms crossed over his mailed chest so that his hands in their heavy cuirasses lay on his shoulders and his sword at his feet, stood propped at a precarious angle against the side, obscuring the elaborate carved letters. "Requisc — " was all he could see. Requiscat in pace. "Rest in peace," a blessing the knight had obviously not been granted. His sleeping face under the carved helmet looked disapproving.

Montoya had draped a thin sheet of plastene over the open top. It was beaded with water. Dunworthy wondered if the other side of the tomb bore a morbid carving of the horror that lay within, like the ones in Colin's illustration, and if it were as ghastly as the reality. Water spilled steadily into the head of the tomb, dragging the plastic down.

Montoya straightened, bringing up with her a flat box filled with mud. "Well?" she said, laying it across the corner of the tomb. "You said you had some more questions?"

"Yes," he said. "You said there wasn't anyone else at the dig when Badri was there."

"There wasn't," she said, wiping sweat off her forehead. "Whew, it's muggy in here." She took off her terrorist jacket and draped it over the tomb lid.

"What about locals? People not connected with the dig?"

"If there'd been anyone here, I'd have recruited them." She began sorting through the mud in the box, unearthing several brown stones. "The lid weighed a ton, and we'd no sooner gotten it off than it started raining. I would've recruited anybody who happened by, but the dig's too far out for anyone to happen by."

"What about the National Trust staff?"

She held the stones under the water to clean them. "They're only here during the summer."

He had hoped someone at the dig would turn out to be the source, that Badri had come in contact with a local, a National Trust staffer or a wandering duck hunter. But myxoviruses didn't have carriers. The mysterious local would have had to have the disease himself, and Mary had been in touch with every hospital and doctory's surgery in England. There hadn't been any cases outside the perimeter.

Montoya held the stones up one by one to the battery-light clipped to one of the supporting posts, turning them in the light, looking at their still-muddy edges.

"What about birds?"

"Birds?" she said, and he realized it must sound as though he were suggesting she recruit passing sparrows to help raise the lid of the tomb.

"The virus may have been spread by birds. Ducks, geese, chickens," he said, even though he wasn't certain chickens were reservoirs. "Are there any at the dig?"

"Chickens?" she said, holding one of the stones half-raised to the light.

"Viruses are sometimes caused by the intersection of animal and human viruses," he explained. "Fowl are the most common reservoirs, but fish are sometimes responsible. Or pigs. Are there any pigs here at the dig?"

She was still looking at him as though she thought he was daft.

"The dig's on a National Trust Farm, isn't it?"

"Yes, but the actual farm's three kilometers away. We're in the middle of a barley field. There aren't any pigs around, or birds, or fish." She went back to examining the stones.

No birds. No pigs. No locals. The source of the virus wasn't here at the dig either. Possibly it wasn't anywhere, and Badri's influenza had mutated spontaneously, as Mary had said happened occasionally, appearing out of thin air and descending on Oxford the way the plague had descended on the unwitting residents of this churchyard.

Montoya was holding the stones up to the light again, chipping with her fingernails at an occasional clot of mud and then rubbing at the surface, and he realized suddenly that what she was examining were bones. Vertebrae, perhaps, or the knight's toes. Recquiscat in pace.

She found the one she had apparently been looking for, an uneven bone the size of a walnut, with a curved side. She dumped the rest back into the tray, rummaged in the pocket of her terrorist shirt for a short-handled toothbrush, and began scrubbing at the concave edges, frowning.

Gilchrist would never accept spontaneous mutation as a source. He was too in love with the theory that some fourteenth- century virus had come through the net. And too in love with his authority as Acting Head of the History Faculty to give in, even if Dunworthy had found ducks swimming in the churchyard puddles.

"I need to get in touch with Mr. Basingame," he said. "Where is he?"

"Basingame?" she said, still frowning at the bone. "I don't have any idea."

"But — I thought you'd found him. When you phoned Christmas Day you said you had to find him to authorize your NHS dispensation."

"I know. I spent two full days calling every trout and salmon guide in Scotland before I decided I couldn't wait any longer. If you ask me, he's nowhere near Scotland. She pulled a pocketknife out of her jeans and began scraping at the rough edge of the bone. "Speaking of the NHS, would you do something for me? I keep calling their number but it's always busy. Would you run over there and tell them I've got to have some more help? Tell them the dig's of irreplaceable historical value, and it's going to be irretrievably lost if they don't send me at least five people. And a pump." The knife snagged. She frowned and chipped some more.

"How did you get Basingame's authorization if you didn't know where he was? I thought you'd said the form required his signature."

"It did," she said. An edge of bone flew suddenly off and landed on the plastene shroud. She examined the bone and dropped it back in the box, no longer frowning. "I forged it."

She crouched by the tomb again, digging for more bones. She looked as absorbed as Colin examining his gobstopper. He wondered if she even remembered that Kivrin was in the past, or if she had forgotten her as she seemed to have forgotten the epidemic.

He rang off, wondering if Montoya would even notice, and walked back to Infirmary to tell Mary what he had found out and to begin questioning the secondaries again, looking for the source. It was raining very hard, spilling off the downspouts and washing away things of irreplaceable historical value.

The bellringers and Finch were still at it, ringing the changes one after another in their determined order, bending their knees and looking like Montoya, sticking to their bells. The sound pealed out loudly, leadenly, through the rain, like an alarum, like a cry for help.

Christmas Eve 1320 (Old Style.) I don't have as much time as I thought. When I came in from the kitchen just now, Rosemund told me Lady Imeyne wanted me. Imeyne was deep in earnest conversation with the bishop's envoy, and I supposed from her expression that she was cataloguing Father Roche's sins, but as Rosemund and I came up, she pointed to me and said, "This is the woman I spake of."

Woman, not maid, and her tone was critical, almost accusing. I wondered if she'd told the bishop her theory that I was a French spy.

"She says she remembers naught," Lady Imeyne said, "yet she can speak and read." She turned to Rosemund. "Where is your brooch?"

"It is on my cloak," Rosemund said. "I laid it in the loft."