A Seattle boy Dade “Zero Cool” Murphy (Jonny Lee Miller) is arrested and charged, at the age of 11, with crashing 1,507 systems in one day and causing a single-day 7-point drop in the New York Stock Exchange. And because of that he was banned to own or operate a computer or touch-tone telephones until his 18th birthday. Before Dade turns 18, his mother takes a new job in a New York City.
When he turns 18, Dade calls a local television station, dupes the security guard into giving him the modem’s phone number (the tactic is known as social engineering) and successfully hacks into the station’s computer network, changing the current TV program to an episode of The Outer Limits. However, Dade is attacked by the hacker (Acid Burn) on the same network, and is eventually kicked off. During the conversation, Dade identifies himself by the new alias, Crash Override. Dade enrolls at Stanton High School, where he meets the beautiful Kate Libby (Angelina Jolie), who is responsible for taking him on a tour of the school.
Dade is being told about the pool on the roof that results of being locked on the roof with the other several students during rainstorm. He learns that Kate is “Acid Burn” a feud erupts between him and Kate. Their eventual hacking duel, which spans most of the film, is judge by Kate and Dade’s mutual friends in the hacking community, the Phantom Phreak, Cereal Killer and Lord Nikon. The real trouble erupts when Joey Pardella (Jesse Bradford), the younger, novice hacker of the group, successfully breaks into an Ellingston Mineral Company supercomputer to prove to the rest of the group that he is an elite hacker.
In order to validate this feat, he downloads part of a garbage file. Unfortunately, the company’s IT employee Hal (Penn Jillette) detects this unauthorized entry into their systems and summons computer security officer Eugene “The Plague” Belford (Fisher Stevens) to deal with the problem. He realizes that the file that is being downloaded can prove that The Plague is stealing money from the company via salami slicing. The Plague enlists the US Secret Service to recover the file by claiming that it is the code to Da Vinci, a computer virus that will capsize the company’s oil tanker fleet stating that he needs that code to destroy the virus.
Joey was arrested and his computer was searched, but he Secret Service finds nothing, as Joey has hidden the disk containing the files in the vent in his room. After being released on parole, Joey reveals the disk to Phantom Phreak in a public park, but they quickly realize that they are being followed by the Secret Service. The next day, Phreak is arrested. He uses his phone call to inform Kate that he hid the disk in a men’s bathroom a school, that evening Kate and Cereal Killer ask Dade for his help but because of his record he states that he can’t get involved.
Kate then asks Dade to copy the disk so that if anyone else is arrested, they have the disk as evidence. After determining that Dade is not the one who hacked into Ellingston, Plague attempts to enlist Dade’s help to find the one who did. First he offers Dade a gift of a free high-powered laptop. Later, he threatens to have Dade’s mother incarcerated with a manufactured criminal record. At this, Dade agrees to deliver Kate’s copy of the disk. Meanwhile, Kate, Lord Nikon and Cereal Killer (a reference to John Draper aka Captain Crunch) attempt to discern the contents of the disk.
Dade joins them, and after working all night, they find out the truth: it’s designed to salami slice $25 million from Ellingston transactions. Dade reveals that he knows Plague is behind this scheme, because he was the one who wanted Kate’s copy of the disk. He admits he gave Plague the disk and reveals his history as Zero Cool. Determined to stop the scheme, the assembled hackers plan to hack the Gibson again. Kate and Dade go dumpster diving for employee memos with passwords, Cereal Killer nstalls a hidden microphone in the Ellingston offices, and Nikon poses as a delivery boy and wanders the Ellingston cubicles, memorizing employee passwords as they enter them. From the memos, they discover the Da Vinci virus, which is set to capsize the fleet the next day, and which would provide the perfect cover to distract from the salami-slicing worm. In need of help, they seek out the help of Razor and Blade, the producers of a hacker-themed pirate TV show, “Hack the Planet. ” The next morning, they evade arrest by the Secret Service and converge on Grand Central station, from whose payphones they begin their assault on the Gibson.
At first, their attempts are easily rebuffed by Plague, who calls Dade to warn him to escape before he is arrested. However, Razor and Blade have contacted hackers around the world, who lend their support with virus attacks, distracting Plague long enough for Dade to download the incriminating file. Shortly after crashing the Gibson, Dade and company are arrested. As they’re being led away, Dade surreptitiously informs Cereal Killer, hiding in the crowd, that he’s tossed the disk in a trashcan.
As Dade and Kate are being interrogated, Razor and Blade jam the local television signals and broadcast live video of Cereal Killer, revealing the plot and Plague’s complicity. Plague attempts to escape to Japan under the alias, “Mr. Babbage”, but is arrested in mid-flight. Their names cleared, Dade and Kate go on a date, Kate even wears a dress as were the stakes if Dade had won their earlier hacking duel. While relaxing in a pool on the roof of a building, Dade shows off his latest hack: the lights in several adjacent office buildings spell out “CRASH AND BURN. “