The story focuses on the lives of Bruno Clément and Michel Djerzinski, two French half-brothers born of a hippie-type mother, described as selfish and narcissistic, who abandoned them both. Michel is raised by his paternal grandmother and becomes
a brilliant but extremely introverted molecular biologist, whose groundbreaking discoveries will ultimately lead to the elimination of sexual reproduction, and the advent of a new humanity altogether.
Bruno's upbringing is much more tragic as described: he is shuffled and forgotten from one abusive boarding school to another,
tries to have a normal life, only to find himself trapped in a loveless marriage and a frustrating career as a high-school french teacher, then grows into a lecherous and insatiable sex addict whose dalliances with prostitutes and sex chat on Minitel do nothing to satisfy him, while his sessions with a bored and cold psychiatrist do not help him at all; he becomes obsessed with his young female students, writes racist pamphlets out of frustration, and matters inexorably escalate to the point where he finds himself on disability leave from his job and in a mental hospital after a failed attempt to engage in sexual activity with a 14-year-old girl of North-African origin. Later, an unexpectedly fulfilling relationship with a free-spirited woman he met at a new-age camp, with whom he came closest he had ever come to love and happiness, who understood him and accepted him with all his flaws, who invited him into the world of
swingers clubs where he could finally act on his devouring sexual desire, ends tragically when she becomes handicapped then commits suicide as she didn't want to be a burden, which further annihilates Bruno's psyche and his hopes of finding happiness; it is implied that he commits to a mental hospital for life.
At the end of the novel it is revealed that Djerzinski's scientific as well as conceptual work (finished just before his likely suicide by drowning) led to what is called the “third metaphysical mutation” – a
transhumanist transition from humanity to a new species of neo-humans, virtually immortal and reproduced by
cloning, in an effort to eradicate dangerous passions which brought down and threatened humanity, as well as the very idea of individuality which Djerzinski held as the root of all evil (a parallel is drawned with
Buddhism), in an effort, furthermore, to restore a sense of shared spirituality and fraternity through the means of science, in a world where the ancient spirituality based on the idea of God, which shaped civilization and provided comfort towards mortality, has long vanished and led to an unbearable void ; and it is actually a neo-human who narrated the story a few decades later, looking back on humans (which are almost extinct by then) with the same mixture of condescendance and compassion humans used to feel when looking back on apes.
