Recently unemployed accountant Morgan Sullivan, [Jeremy Northam], is bored with his suburban life. Pressured by his wife to take a job with her father's company, he instead pursues a position in corporate espionage. Digicorp's Head of Security, Finster, [Nigel Bennett] inducts Morgan and assigns him a new identity. As Jack Thursby, he is sent to conventions to secretly record presentations and transmit them to headquarters. Sullivan is soon haunted by recurring nightmares and neck pain.
At a bar, Rita Foster, [Lucy Liu], from a competing corporation, offers him pills and tells him not to transmit at the next convention. Afterward, Digicorp confirms the receipt of his non-existent transmission. He takes the pills Rita gave him and his nightmares and pains stop. Confused and intrigued by Rita, he arranges to meet with her again. She tells him about Digicorp's deception and offers him an antidote — a green liquid in a large syringe. Morgan hesitantly accepts. She warns him that no matter what happens at the next convention he must not react.
Morgan discovers that all the convention attendees believe themselves to be Digicorp spies. While they are drugged from the served drinks, plastic-clad scientists probe, inject and brainwash them. Individual headsets reinforce their new identities, preparing them to be used and then disposed of. Morgan manages to convince Digicorp that he believes his new identity. He is then recruited by Sunway Systems, a rival of Digicorp. Sunway's Head of Security, Callaway, [Timothy Webber], encourages Morgan to act as a double agent, feeding corrupted data to Digicorp. Morgan calls Rita, who warns him that Sunway is equally ruthless, and that he is in fact being used by Rita's boss, Sebastian Rooks. Morgan manages to steal the required information from Sunway Systems' vault, escaping with Rita's help.
Rita ultimately takes him to meet Rooks. When she temporarily leaves the room, a nervous Morgan calls Finster, [Nigel Bennett], and becomes even more distressed. He accidentally shoots Rita, who encourages him to ignore her and meet Rooks in the room next door. Morgan finds the room filled with objects which appear to be personal to him, including a photograph of him and Rita together. Realising that he is apparently Rooks, he turns to Rita in disbelief.
Before Rita can convince him, the apartment is invaded by armed men. Rita and Morgan escape to the roof of the skyscraper as the security teams of Digicorp and Sunway meet, led by Finster and Callaway. After a short Mexican standoff both sides realise they are after the same person, Sebastian Rooks, and rush to the roof, where they find Morgan and Rita in a helicopter. Rita cannot fly it, but, having designed it himself, Sebastian can after Rita encourages him to remember his past self, connecting through his love for her. He lifts off amid gunfire from the security teams. Finster and Callaway comment as the couple seem to have escaped:
Looking up, they see the helicopter hovering and realise, too late, the true identity of Morgan Sullivan. Sebastian triggers a bomb, causing the whole roof to explode. On a boat in the South Pacific Ocean, Sebastian reveals the content of the stolen disc to Rita. Marked "terminate with extreme prejudice", it is the last copy of Rita's identity (after the one in the vault was destroyed). Sebastian throws the disc into the sea and says, "Now there's no copy at all."
