I'm brilliant, she thought. Yes! Dad would be proud.

She made some sketches, and by that time it was after six. Time to go home.

Knickers was waiting by the door, and she gave Ally a dirty look and some very disapproving barks. By way of penance, Ally took her on an extra long walk, all the way up to Fourteenth Street and back. Then she picked up some tuna salad and steamed veggies from a new deli on West Tenth Street.

As she settled down to eat at the breakfast bar, she felt like a single mom, always eating and doing everything on the run—and all she had to worry about was a friendly dog. How did real working moms do it?

It was just past nine when she poured a glass of Chardonnay and picked up Grant's envelope and took it into the living room, pausing to put some Chopin ballades on the CD player.

The envelope contained a bound folder that was Dr. Karl Van de Vliet's curriculum vitae, his resume. It was in fact a minibiography that devoted a page to each of his career turns. His life story was presented from a god's‑eye view, as though it were a novel.

Karl Van de Vliet had done his undergraduate studies at the prestigious University of Maastricht after which he'd migrated to the United States and taken a Ph.D. in molecular genetics from the University of Chicago, top of the class. Following that he went to Yale as a postdoctoral fellow, again studying genetics.

From the beginning he focused his research on the mechanisms that govern human cell reproduction. Along the way he'd become interested in something known as the Hayflick limit—which concerned the number of times a cell could divide before it became senescent and ceased to replicate. This natural life span controlled the aging process of every organism, and it seemed to be nature's device for nipping undesirable (i.e. mutant) cells in the bud by never letting any cell, unhealthy or healthy, just keep on replicating indefinitely.

However, there were "immortal cells" buried within us all, so‑called stem cells that could replicate forever, unchanged. They were present at the very beginning of life and all our differing body tissue was created from them. Some still lingered on in our body, as though to be available for spare parts. If one could figure out how to transfer the characteristics of those cells to other cells, then the possibility existed that we could regenerate damaged or aging tissue in our vital organs. The trick was to figure out the mechanism whereby stem cells managed to cheat time.

His research, which was accompanied by a flurry of scientific papers, was celebrated and encouraging. After three years he was lured away from Yale to become a faculty member at Johns Hopkins, which offered to double his laboratory budget. He was there for six years, during which time he met Camille Buseine, a neurosurgeon finishing her residency.