“Who are you?” Susan suddenly challenged. “What are you doing in my room? Get out of here.” Her voice had risen to a shout, bringing the nurse in at a run.

Zachary said nothing during this short tirade. It had happened in the past, and nothing he had said on those occasions comforted her. She needed the nurse, whom she recognized on some level. He quieted her down, and she went back to watching the birds.

After his initial success in nonmedical nanotechnology, Berman had invested heavily and hired the best minds he could afford to move the company into the medical realm, particularly after the breakthroughs they’d managed in molecular manufacturing. It had been Berman’s idea to mimic the way living cells used ribosomes to manufacture proteins that had put Nano way ahead of the competition in the molecular manufacturing nanorobot arena. With his continued urging, the first product of this method was the Nano microbivore, which had been theoretically designed more than a decade previously.

At the same time the microbivore molecular manufacturing project was under way, Berman launched a private investigation of Alzheimer’s disease. More than a few of the scientists Berman had hired at Nano were working on diagnostic tests for Alzheimer’s with the idea that the earlier the protein buildup could be detected, the better chance doctors had of slowing the spread of the disease. It stood to reason. It was around that time that Berman had allowed himself to be secretly tested for the predictive gene, which only served to heighten his general anxiety.

As the light began to fade outside the window of his mother’s room, Berman slowly got to his feet. He truly hated coming to visit her. In a strange way he thought it was disrespectful to her as a person. Inwardly he suspected that if she knew how she was going to end up, she’d be the first to tell him not to come but rather to remember how she had been as a loving mother.

Without trying to say good-bye, Zachary descended the long hall toward the lobby of the facility, breathing shallowly to avoid the smell. He was disgusted, and hated himself for it, knowing as he did how tenuous the threads of nerve fibers were that separated his mental state from that of his mother’s.

Berman emerged into the gathering gloom as the sun had settled behind the mountains to the west. Darkness fell rather quickly as he walked across the lawn and the parking area on his way to his Aston Martin.

With the engine purring under the hood, Berman checked his watch again. It was time to go back to the lab and find out what it was that Stevens, the investigative leader on the Chinese study, who had texted him yet again, wanted to talk to him about so urgently. It sounded ominous, and Berman did not like surprises. Pulling out onto the road, Berman laid a strip of rubber as a defiant adolescent gesture.