Dr. Lawrence Angelo works for Virtual Space Industries, running experiments in increasing the intelligence of chimpanzees using drugs and virtual reality. One of the chimps escapes using warfare technology that he was being trained to use. Dr. Angelo is generally a pacifist, who would rather explore the intelligence-enhancing potential of his research without applying it for military purposes.
Jobe Smith, a local greenskeeper with an unspecified learning disability, lives in the garden shed owned by the local priest, Father Francis McKeen. McKeen's brother, Terry, is a local landscape gardener and employs Jobe to help him with odd jobs. Father McKeen punishes the challenged Jobe with a belt whenever he fails to complete his chores.
While Dr. Angelo records audio notes about needing a human subject, Jobe is mowing his lawn. Peter Parkette, the young son of Dr. Angelo's neighbors, is friends with Jobe. Dr. Angelo invites Peter and Jobe to play some virtual reality games. Learning more about Jobe, Angelo persuades Jobe to participate in his experiments, telling him that it will make him smarter. Jobe agrees and begins a program of accelerated learning. Dr. Angelo makes it a point to redesign all the intelligence-boosting treatments without the "aggression factors" used in the chimpanzee experiments.
Jobe soon becomes smarter, for example, learning Latin in two hours at the lab. Dr. Angelo starts taking Jobe to his lab at work to use the technology there. Jobe begins a sexual relationship with a young rich widow, Marnie. However, Jobe starts to have telepathic and hallucinatory experiences. He continues with the experiments at the lab, until an accident makes Dr. Angelo call a halt. The project director, Sebastian Timms, employed by a mysterious agency known as The Shop, keeps a secret watch on the progress of the experiment, and swaps the scientist's new medications for the old Project 5 "aggression factors".
Jobe acquires telekinetic and pyrokinetic powers and takes Marnie to the lab to have sexual intercourse with her in virtual reality. Something goes wrong in the simulation, and Marnie is driven insane, laughing endlessly at nothing.
Jobe's powers and abilities continue to grow, although the treatments also affect his mental stability, and he takes revenge on those who abused him when he was "dumb": Father McKeen is engulfed in flames, a bully named Jake is put into a catatonic state by a mental "lawnmower man" continually mowing his brain, and a lawnmower invention of Jobe's runs down Harold, Peter's abusive father. Jobe uses his telepathic abilities to make the investigating police attribute it all to "bizarre accidents" in front of Dr. Angelo.
Jobe believes his final stage of evolution is to become "pure energy" in the VSI computer mainframe, and from there reach into all the systems of the world. He promises his "birth" will be signaled by every telephone on the planet ringing simultaneously. The Shop sends a team to capture Jobe, but they are ineffective against his abilities and he scatters their molecules. Jobe uses the lab equipment to enter the mainframe computer, abandoning his body to become a wholly virtual being. In the process his body becomes a wizened husk.
Dr. Angelo remotely infects the VSI computer with a virus that encrypts all of the links to the outside world, trapping Jobe in the mainframe. As Jobe searches for an unencrypted network connection, Dr. Angelo primes bombs to destroy the building. Feeling responsible for what has happened to Jobe, Angelo then joins him in virtual reality to try to reason with him. Jobe overpowers and crucifies him, then continues to search for a network connection. Peter runs into the building; Jobe still cares for him and allows Dr. Angelo to go free in order to rescue Peter. Jobe forces a computer-connected lock to open, allowing Peter and Dr. Angelo to escape. Jobe escapes through a Backdoor as the building is destroyed in multiple explosions.
Back at home with Peter, Dr. Angelo and Peter's mother Carla (who has become a romantic interest) are about to leave when their telephone rings, followed by the noise of a second, and then hundreds, all around the globe."