The film focuses on its protagonist, a programmer named Peter who works for a company named Initech. Peter is dissatisfied with his life, both the personal one and the professional one and he had fallen into a boring routine. His life changes when the workers are told that a consultant will arrive to help improve the efficiency at the work place. Dissatisfied, Peter and his two close friends, Samir and Michael, plan to express their dissatisfaction in various ways such as trashing the printer.
At the end of the week, Peter and his girlfriend go to an occupational hypnotherapist, hoping that he will be able to help Peter relax more and change the way he views life. The appointment does not go the way Peter wanted, as the therapist dies while Peter is in a trance and thus Peter remains trapped in that state of mind.
On Monday, Peter is a completely different man, refusing to go to work and explain himself to his boss. As a result, Peter is dumped by his girlfriend and decides that he wants to stop going to work. Peter also goes to a waiter he secretly liked named Joanna and he asks her out. The two agree to meet later at Peter’s apartment and Peter decides to go to his office where he meets with two men named Bob who interview him. Peter is sincere about what motivates him and about his dissatisfaction with his work and the two men are impressed by Peter’s sincerity.
Peter stops going to the office for a few days and he decides to spend his time fishing and lounging with Joanne. When Peter returns to the office, he finds that he was promoted but that his two close friends have been fired. As a way of getting revenge, the three plan to release a viruses that will rob the company systematically in such a way that no one will realize what is happening.
Peter tells Joanne about the scam but she is not happy with it, claiming that what they do is stealing.
On Monday, when Peter wakes up, he finds that more than 300,000 dollars were in the account set by him, Samir and Michael. Peter decides to return the money and to turn himself in but first he goes to Joanne and tells her what he plans to do. Joanne forgives him for the fight they had and Peter goes to his office in the middle of the night with an envelope containing a check with the money and a confession letter. Peter then returns home, determined to go to the office the next day.
The next day however, when Peter goes to the office, he sees it burning. Peter also sees one if his coworkers, a man named Milton who threatened to burn the building to the ground on many occasions. The film ends with Peter, now working in a construction crew, cleaning the debris from his former office building and sometimes meeting with his friends. The three all agree to never mention the incident again, telling themselves that their conscience is clear since they did try to return the money.
