Margaret Atwood's novel Oryx and Crake takes place in a future world where scientific achievements and particularly genetic experimentation are the focus of society. Mankind's obsession with science ultimately allows the ethically blind idealist Crake to destroy human society.

The protagonist, Jimmy, is the only son of two genetic scientists. His mother quits working when he is young, due to an untreated nervous breakdown. Jimmy's father rises to prominence as a researcher but fails as a father. His father does not understand that young children do not understand ironic humor, so he has a hard time communicating with Jimmy. Both of Jimmy's parents usually forget his birthday.

Jimmy's mother abandons the family and escapes into the pleeblands (dirty, lawless cities) when Jimmy is a teenager. He finds it hard to make friends and only really talks to his classmates when he is creating comedic skits to entertain them. Midway through high school, Jimmy befriends Crake, a transfer student. Jimmy and Crake share similar online and gaming interests, and they bond over their obsession with a child porn star who will later be known as Oryx.

Although Jimmy is intelligent in using words, he graduates from HelthWyzer High as an average student. He gets accepted at a third-rate college, the Martha Graham Academy, where he studies problematics. After graduation, Jimmy takes a job as a librarian but gets fired because he cannot bear to throw out books. His next job involves writing ads for self-help products. Even though Jimmy doesn't have any interest in his work, he has a knack for what he does and soon starts climbing the corporate ladder.

Jimmy finds it easy to relate to women sexually but hard to have intimate emotional connections. By his mid-twenties, he has given up on romance and settled for a collection of married sex partners. However, his interest in women fades when Jimmy falls into a depression after learning that his mother has been executed for treason.

Crake re-enters Jimmy's life while Jimmy is feeling depressed. Crake, a brilliant scientist, now works for Paradice, a project in the RejoovenEsence compound. Crake hires Jimmy to work on an ad campaign for BlyssPlus, a Viagra-type drug that will clandestinely sterilize its users. Trusting his old friend, Jimmy doesn't stop to ponder the ethics of the product. While working with Crake at the RejoovenEsence compound, Jimmy meets Oryx and finds that he is as attracted to her as ever. Oryx, who has been subjected to sexual abuse from her early days as a child porn star to her later experiences as a prostitute, works for RejoovenEsence as well. She teaches simple botany and zoology to the children of Crake, a genetically altered humanoid species that lives in the bio-bubble at Paradice. Although Oryx is officially Crake's girlfriend, Jimmy and Oryx start an affair.

Crake places Paradice under Jimmy's charge in the event that something should happen to Crake. One night Oryx and Crake disappear, and then Jimmy learns from news reports that a viral plague has broken out worldwide. The virus was transmitted via BlyssPlus. Later that evening, Crake stages his own death. He uses Jimmy's love for Oryx and slits her throat so that Jimmy will shoot him.

After several weeks of remaining locked in Paradice, watching humanity die out on the TV news, Jimmy decides that he must lead the Crakers to a green area where they will have enough food to survive. He tells them that his name is Snowman. Once out of the compound and settled in an arboretum near the sea, Snowman continues to protectively monitor the Crakers from a distance. Meanwhile he suffers from starvation, bug bites, the threat of wild animal attacks and the idea that he is losing his mind.

Finally, Snowman decides that he must return to Paradice to get more food and supplies. While at the RejoovenEsence compound, he sees corpses and the remnants of ordinary human life. He injures his foot while running away from pigoons that threaten to attack him. Snowman makes his way to Paradice via a rampart that runs the length of the compound.

After Snowman replenishes his supplies, he heads back to the arboretum. The Crakers tell him that they have been visited by three people like him. Snowman follows his fellow survivors' tracks to the beach and sees them sitting before a campfire. He is about to approach the trio as the novel ends.