Thirty minutes later, head down against the world, barely aware of the direction he was going, Nicholas Marten walked the all but deserted Sunday-night streets of the city.

He tried not to think of Caroline. Tried not to acknowledge the pain that told him she was no more. Tried not to think that it had been little more than three weeks since she had lost both her husband and son. Tried to put out of his mind the idea that she might have been intentionally given something that caused her fatal infection.

"Something has been done to me." Her voice suddenly echoed inside him as if she had just spoken. It resonated with the same fear and vulnerability and anger it had had when she had first called him in England.

"Something has been done to me." Caroline's words came again. As if she were still trying to reach him, trying to make him believe without doubt that she had not been merely ill, but murdered.

What that "something" was, or at least what she thought it was and how it had begun, she'd told him during the first of the only two lucid moments she'd had since he arrived.

It had happened following the twin funerals of her husband, Mike Parsons, a well-respected forty-two-year-old congressman from California in his second term in office, and their son, Charlie.