PAYCHECK

In the near future, Michael Jennings (Affleck) is a reverse engineer; he analyses his clients' competitors' technology and recreates it, often adding improvements beyond the original specifications. To protect his clients' intellectual property and himself, Jennings, with the aid of his friend Shorty (Giamatti), undertakes a memory wipe to remove knowledge of his engineering.

Jennings is approached by his old college roommate, James Rethrick (Eckhart), the CEO of the successful Seattle technology company Allcom. Rethrick proposes a lengthy three-year reverse engineering job to Jennings, requiring him to live on Allcom's secured campus until its conclusion but rewarding him handsomely with company stock. Jennings agrees and, after arranging for his long-term absence, arrives at Allcom, turns in his personal possessions, and is given a brief tour of the facility where he meets and flirts with botanist Dr. Rachel Porter (Thurman). He is injected with a long-term memory marker for the post-job memory wipe.

Three years later (June 2007), at the conclusion of the memory wipe, Jennings is sitting in Rethrick's office, being thanked for a successful job. On returning home, Jennings finds that, although his Allcom shares would have been worth around $92 million, he had signed them away near the end of his tenure. Furthermore, he finds that his personal possessions have been replaced with an envelope containing a random assortment of everyday items. Soon after, the FBI captures him; and Agent Dodge (Morton) interrogates him on charges related to the death of physicist William Dekker. Jennings is able to escape custody, finding that the items in the envelope can be used at the right time to evade capture. After warning Shorty of his plight, he finds the items pointing him to a café meeting with Porter. Rethrick, who has been watching Jennings' movements, discovers a message to Porter about this meeting and sends a body double to take her place to try to recover the envelope. The real Porter shows up and helps Jennings escape from both the FBI and Rethrick's men.

They take shelter at a local school, examining the remaining items in the envelope while Porter tries to convince Jennings of the relationship they shared during his tenure at Allcom. One of the stamps holds a microdot that, on enlargement, reveals several pictures of newspaper headlines taken from a machine's display showing Allcom becoming financially successful with a device that can depict future events, but the resultant doomsday visions ultimately lead to a series of self-fulfilling prophecies resulting in financial panic, political strife and America launching a pre-emptive nuclear strike. Jennings realizes he must have built this device based on Dekker's invention and, on realizing the horrors that will come, prepared the envelope, using the forecasts from the machine to allow his future self to return to Allcom and destroy the machine. Furthermore, as Rethrick shortly discovers, Jennings rigged the device to malfunction, preventing Rethrick from anticipating Jennings' actions.

Jennings and Porter return to Allcom and make their way to the machine room undetected, jamming the door behind them. Jennings determines the location of the defective circuit and removes it, subsequently rigging the machine to explode in a few minutes. Jennings uses the machine one last time, seeing a vision of himself being shot by an FBI agent in the catwalks above the machine. Soon, Rethrick's men storm the room and, after a brief shootout, Jennings and Porter escape to the catwalks. Rethrick is waiting there, holding them at gunpoint, the same tableau Jennings previously saw. When Jennings' watch, taken from the envelope, beeps, Jennings ducks in time to avoid the FBI Agent's bullet that then kills Rethrick. The machine is destroyed, and Jennings and Porter escape the FBI in the chaos. When Agent Dodge and his men arrive and investigate, they take sympathy and report Jennings killed in the destruction.

In the film's conclusion, Jennings, Porter, and Shorty have opened a greenhouse nursery. Jennings recalls a fortune cookie note from the envelope and discovers one last act he had done with the machine, foreseeing the results of a $90 million lottery and leaving the winning ticket in Porter's birdcage.