He prowled among the ruins like a homeless spirit, then descended the wall and made his way back to the monastery's second-floor dining room. The fifteenth-century monastery was one of the traditional buildings the Greek government operated as guest houses around the country. MacLean made a point of arriving for breakfast after all the other guests had left to go sightseeing.

The young man cleaning up in the kitchen smiled and said, "Kali mem, Dr. MacLean

“Kali mera, Angelo,” MacLean replied. He tapped his head with his forefinger. “Did you forget?”

Light dawned in Angelo's eyes. "Yes. I'm very sorry. Mr. MacLean

“That's quite all right. Sorry to burden you with my strange requests,” MacLean said in his soft Scottish brogue. “But as I said before, I don't want people thinking I can cure their upset stomachs and stomachaches.”

“Neh. Yes, of course, Mr. MacLean I understand.”

Angelo brought over a bowl of fresh strawberries, honeydew melon and creamy Greek yogurt, topped with local honey and walnuts, and a cup of thick black coffee. Angelo was the young monk who served as resident hostler. He was in his early thirties, with dark curly hair and a handsome face that was usually wreathed in a beatific smile. He was a combination concierge, caretaker, chef and host. He wore ordinary work clothes and the only hint of his vows was the rope tied loosely around his waist.

The two men had struck up a strong friendship in the weeks MacLean had been a guest. Each day, after Angelo finished his breakfast work, they would talk about their shared interest, Byzantine civilization.

MacLean had drifted into historical studies as a diversion from his intense work as a research chemist. Years ago his studies had taken him to Mystra, once the center of the Byzantine world. He had drifted down the Peloponnese and stumbled upon Monemvassia. A narrow causeway flanked by the sea was the only access to the village, a maze of narrow streets and alleys on the other side of the wall whose “one gate” gave Monemvassia its name. MacLean had fallen under the spell of the beautiful place. He vowed to return one day, never thinking that when he came back he'd be running for his life.

The Project had been so innocent at first. MacLean had been teaching advanced chemistry at Edinburgh University when he was offered a dream job doing the pure research that he loved. He'd accepted the position and taken a leave of absence. He threw himself into the work, willing to endure the long hours and intense secrecy. He led one of several teams that were working on enzymes, the complex proteins that produce biochemical reactions.