Wallace agreed. "A dark-skinned queen who could cure the sick."

"And to Marco, she was possibly an early pagan incarnation of the Black Madonna." Gray looked out toward the island as the boat churned into the choppier open waters. "Perhaps even the legends of the sorceress Morgan Le Fay and Avalon tie back to that same mythology. Another woman bearing magical healing powers."

Rachel's eyes widened. "No wonder Father Giovanni became obsessed with this place."

"For that reason, and also the key." Wallace folded his arms and easily rolled with the boat's motion.

"The key to the Doomsday Book?" Rachel asked. "I thought you said that was rubbish."

"I may have thought it was rubbish, but Marco didn't. All the legends of the key suggest that it unlocked a vast treasure, a treasure that could save the world. Marco believed I was on the right course in studying the places marked as 'wasted.' And I'm growing to think he's right."

"Why's that?" Gray asked.

"Father Rye's stories. He spoke of how the Fomorians battled the invading Celts by casting plagues on them. It was said the Druids did the same when the Romans invaded. So it makes me wonder if the Celts learned something from the conquered Fomorians, something more than just agriculture. A new means of warfare, a new weapon. Maybe there was a core of truth behind these stories. A truth buried in the Domesday Book."

Rachel began to get a glimmer of where he was headed, but Gray got there first.

"You think that ability to cast plagues survived into the eleventh century. Maybe an early form of biowarfare."

Rachel pictured the condition of the mummies. Emaciated, with mushrooms growing internally.

"Could someone have poisoned these villages with some sort of fungal parasite?" Gray asked. "And if so, who?"

"As I said before, all the villages noted in the Domesday Book were located in places of friction between Christians and pagans. And I think it's especially telling that the first place struck was Bardsey Island. Hallowed ground for the Druids. They could not have liked the monks and Christians being here."

"So you think some secret sect of Druids wiped them out?"

"And after that, they took their war to the mainland of England. I suspect they began casting these plagues in the borderlands in hopes the conflict would spread throughout England."

Wallace had to catch himself as the ferry hit a huge wave. Once reseated, he continued. "Perhaps the hidden purpose of the Domesday Book was to map these incursions, to keep track of them. The census takers who compiled the book were sent out to all corners of Britain, collecting information from villagers and townspeople alike, surely doubling as spies."

"Did it work?" Rachel asked, caught up in the story.

"Well, those hot spots never did spread," Wallace said with a shrug. "Someone must have found a way to thwart the attacks. Then buried it safely away."

"The key to the Doomsday Book," Gray said. "You believe it's some sort of cure."

Wallace touched the tip of his nose, acknowledging the same.

"And we're on the right track?" Gray asked, glancing significantly at Rachel. They didn't have much room for error.

His hand slipped over hers, squeezed her fingers, then let go. She wished he had kept on holding. His skin had been hot, his grip reassuring.

Wallace answered Gray's question. "Marco certainly believed in the key. And judging from that gruesome little keepsake of his, he discovered something. And we know he started here at Bardsey."

The professor nodded toward the growing bulk of the dark island. It was buried in the storm. And a moment later, so were they. The winds kicked up, blowing freezing slaps of water across the boat. Then rain suddenly pounded the boat, as if trying to drive them under the sea. Visibility dropped to yards.

"Hang tight!" Kowalski bellowed from the pilothouse, where he stood with the captain. "Swells dead ahead!"

The bow of the boat rose high, pointed at the sky-then dropped like a rock. After that, motion became a blur. The ferry lurched and heaved, rocked and pitched.

Without warning, Rachel's stomach did the same. A queasy heat swept through her. Her hands went clammy and cold. She didn't have time to make it to the ship's water closet. She swung around in her seat, bent over the rail, and emptied her stomach in a single large wrack of her body. It left her so drained she had a hard time keeping a grip on the wet rail.

Below her face, the sea surged up and down, looking ready at any moment to wash up and over her. Her hands slid. She felt herself tipping.

Then strong arms closed around her, holding her firmly but gently.

"I've got you," Gray said.

She leaned against him, her stomach still rolling with the waves. The rest of the trip was no smoother, but he never left her side.

After what seemed like hours, land filled the world ahead. The storm grew less fierce. Rain receded to a drizzle. A long concrete slipway stuck out into the small harbor, next to it a stone jetty. The ferryman slid his boat skillfully beside the dock as Lyle ran and tossed bolsters between the jetty and the boat. Moments later, they were tied up.