Toni and the two men were working the phones, calling everyone who had a pass to the top-security laboratory. There were four biosafety levels. At the highest, BSL4, the scientists worked in space suits, handling viruses for which there was no vaccine or antidote. Because it was the most secure location in the building, samples of the experimental drug were stored there.

Not everyone was allowed into BSL4. Biohazard training was compulsory, even for the maintenance men who went in to service air filters and repair autoclaves. Toni herself had undergone the training, so that she could enter the lab to check on security.

Only twenty-seven of the company's staff of eighty had access. However, many had already departed for the Christmas vacation, and Monday had turned into Tuesday while the three people responsible doggedly tracked them down.

Toni got through to a resort in Barbados called Le Club Beach and, after much insistence, persuaded the assistant manager to go looking for a young laboratory technician called Jenny Crawford.

As Toni waited, she glanced at her reflection in the window. She was holding up well, considering the late hour. Her chocolate-brown chalk-stripe suit still looked businesslike, her thick hair was tidy, her face did not betray fatigue. Her father had been Spanish, but she had her Scottish mother's pale skin and red-blond hair. She was tall and looked fit. Not bad, she thought, for thirty-eight years old.

"It must be the middle of the night back there!" Jenny said when at last she came to the phone.

"We've discovered a discrepancy in the BSL4 log," Toni explained.

Jenny was a little drunk. "That's happened before," she said carelessly. "But no one's ever made, like, a great big drama over it."

"That'sbecause I wasn't working here," Toni said crisply. "When was the last time you entered BSL4?"