Alicia Klein's world as she knows it is about to change. A 27-year-old law school dropout, she responds to a Google ad seeking offspring of sperm donor #4299 for a well-paid experiment.

A month later, she meets her 97 half-siblings on a Caribbean island. They soon discover that they are all the biological children of Tom ("Mac") MacDonald, a renowned biologist who has gained a fortune with the pioneering biotech giant, Macgenetics.

At first, Alicia is thrilled to be a part of the experiment and discover all her new brothers and sisters, but events soon turn ominous. Mac handpicks a group of siblings to partner with each other and produce the next generation of children who will take the lead in the genetic revolution. He promises that their children will foster a better, non-violent world.

Torn by doubt, Alicia finally accepts her sibling Jeff, a charismatic robotic engineer. Their sexual relationship is fraught with unusual physical pain, but eventually they have a child, Laura, who is unlike other reading at 6 months, programming at 18 months.

While Laura and her equally unusual cousins grow up swiftly, ancient animals reappear, and it is not unusual for a kindergarten to have sets of ten identical children. Alicia increasingly wonders if Mac really wants to eliminate human violence and save the species, as he claims, or is he a power-hungry genius, pulling the strings of his creation?