TWO tired men looked at Antonia Gallo with resentment and hostility in their eyes. They wanted to go home, but she would not let them. And they knew she was right, which made it worse.

All three were in the personnel department of Oxenford Medical. Antonia, always called Toni, was facilities director, and her main responsibility was security. Oxenford was a small pharmaceuticals outfit- a boutique company, in stock market jargon-that did research on viruses that could kill. Security was deadly serious.

Toni had organized a spot check of supplies, and had found that two doses of an experimental drug were missing. That was bad enough: the drug, an antiviral agent, was top secret, its formula priceless. It might have been stolen for sale to a rival company. But another, more frightening possibility had brought the look of grim anxiety to Toni's freckled face and drawn dark circles under her green eyes. A thief might have stolen the drug for personal use. And there was only one reason for that: someone had become infected by one of the lethal viruses used in Oxenford's laboratories.

The labs were located in a vast nineteenth-century house built as a Scottish holiday home for a Victorian millionaire. It was nicknamed the Kremlin, because of the double row of fencing, the razor wire, the uniformed guards, and the state-of-the-art electronic security. But it looked more like a church, with pointed arches and a tower and rows of gargoyles along the roof.

The personnel office had been one of the grander bedrooms. It still had Gothic windows and linenfold paneling, but now there were filing cabinets instead of wardrobes, and desks with computers and phones where once there had been dressing tables crowded with crystal bottles and silver-backed brushes.