There are 4 billion people on Earth. 237 are Scanners. They have the most terrifying powers ever created… and they are winning.
Private security firm ConSec plans to showcase potential “scanners”, people with exceptional powers of telekinesis, telepathy, and mind control. However, when ConSec’s scanner attempts to read the mind of a volunteer from the invited group, the scanner’s head explodes. ConSec officials surmise that the volunteer was himself a scanner and initially take him into custody. However, he is able to use his powers to kill the men guarding him and escape.
ConSec security head Braedon Keller advocates shutting down scanner research, but program head Dr. Paul Ruth disagrees, noting that the assassination and escape have shown the weapon’s potential they had sought to demonstrate. Ruth attributes the operation to a scanner named Darryl Revok (Michael Ironside), who Ruth says has his own underground network of scanners in competition with ConSec’s program. He argues that ConSec should recruit scanners to their cause to infiltrate and bring down Revok’s group.
To this point, scanner Cameron Vale has lived an unhappy life as a social outcast, due to his inability to cope with the unceasing stream of other people’s thoughts bombarding his mind and his not even knowing the cause or nature of his condition. After bringing Vale into ConSec, Ruth has administered a drug called ephemerol, which inhibits his scanning ability. Ruth asks for Vale’s help, explaining that he is a scanner and that Revok is killing all scanners who refuse to join him.
With Keller working for him as a spy, Revok learns of Ruth’s plan and dispatches assassins to follow Vale as he begins his search for Revok by visiting a scanner named Benjamin Pierce. They kill Pierce. Before he dies, Vale reads from his mind a name – Kim Obrist. Vale tracks down Obrist, who has formed a telepathic alliance with a group of other scanners. Vale attends a meeting, but assassins for Revok strike again, with only Vale and Obrist escaping. Scanning an assassin, Vale learns of a drug company, which he then infiltrates. He finds that large quantities of ephemerol are being distributed under a program called “Ripe,” run by Revok himself through ConSec. Vale and Obrist return to ConSec, where Ruth suggests Vale scan the computer system to learn more about Ripe. Meanwhile, Keller tries to kill Obrist, but she escapes. Keller kills Ruth while Vale and Obrist flee the building.
Vale accesses the computer network through a telephone and pulls ephemerol shipment information. When Keller discovers this, he orders the computer system destroyed while Vale is plugged into it. The plan backfires and the computer explodes, killing Keller and leaving Vale and Obrist to investigate the shipments. They visit a doctor on the list of recipients, where Obrist suddenly discovers she is being scanned by the unborn baby of a pregnant woman. Vale concludes that Ripe’s purpose is to disseminate ephemerol to pregnant women, making their babies scanners. The two are ambushed by Revok’s men and abducted.
Revok reveals that ephemerol was a tranquilizer developed by Ruth for pregnant women that had the unintended side effect of causing the unborn children to become scanners. Ruth learned of this from providing the drug to his own wife during her pregnancies. The two resulting children were Revok and Vale, who, as the longest-term scanners are more powerful than any other scanners. By mass distributing ephemerol, Revok plans to create a new generation of scanners, giving him the manpower to execute a plan of global domination over non-scanners, with Revok heading this new empire. Revok asks Vale to join, but Vale refuses and the two have a final scanning showdown against one another: their battle causes the blood vessels in their bodies to begin to burst open – Vale’s body ignites and his eyes explode, while Revok’s eyes turn white and he shouts in agony.
Soon thereafter, Obrist enters the room to find a charred body on the floor. She hears Vale’s voice coming from the corner of the room: in the corner is Revok – his head scar gone and his eyes the same blue as Vale’s. He faces Obrist and announces, “We’ve won”, in Vale’s voice.