Edward Albright, an operative for the Janus corporation, is watching over a prisoner exchange in Paris. He meets up with a Russian spy, Natasha, to gain information on the location of man named Uzi. Edward's handler at Janus, Mavis, has asked Edward to bring Natasha in for questioning. But after sleeping with her and getting what information he can, she attempts to kill him, so he eliminates her.
Edward returns to Los Angeles after his trip to Paris and joins Mavis in her office at the Janus headquarters. Mavis is upset that Edward killed Natasha rather than bring her into Janus as originally ordered. Mavis assumes that he killed her to save her from torture because he'd developed feelings for her. Edward adamantly denies that was the case.
Edward heads into the elevator at Janus to make his switch to Henry Spivey, his alter personality, before entering the AJ Sun offices. The personality switch is triggered in the elevator where memories from Henry's fake trip are transplanted to seem authentic. Edward goes "to sleep" and wakes up as...
Henry is greeted by his assistant at the AJ Sun elevator. He has returned from a conference in Akron, Ohio. Once he is settled in the office, he heads to an appointment with the company shrink, Nora Skinner.
In his therapy session, Henry describes a dream he had where he was in Paris with a beautiful woman. Henry shows Nora a matchbook he found in his pocket from the hotel in Paris. He asks her if she's ever brought back a souvenir from a dream.
Henry returns home and is greeted by his wife, Angie, and their two children. Later that night, in bed, Henry reads a book while Angie sleeps next to him. His vision goes fuzzy and all of sudden, Edward wakes up. He leans over and smacks Henry's wife in the butt. He goes downstairs and calls Tony at Janus to find out why he woke up, thinking he has to go out on a mission. To Tony's disbelief, the computer shows Edward as still being asleep. Apparently these things don't happen, so Tony lets Edward know that there isn't a protocol for such things.
The next morning, Henry steps off the elevator at the AJ Sun offices and meets up with Tom, his friend and co-worker. Before Henry can even sit down, he is told he has to leave on a business trip. His assistant walks him to the elevator. Just as the door closes, she speaks into a walkie talkie to let Tony know that Henry is "in the box." Just then, Henry goes to sleep and Edwards wakes.
Mavis lets Edward know that Uzi has put a price on his head and they will be sending Raymond after him. However, Edward manages to persuade Mavis to send him as well. In Russia, Edward is waiting for Raymond's call so he can take the shot on Uzi. Just as a clear shot is available, Henry wakes up. Raymond calls out "Avenger," which is Edward's cue to step down and not take the shot. Henry, unclear what is going on, accidentally fires the gun, sending everyone into a frenzy and alerting them to his position.
Henry runs through the halls trying to escape, and one of Uzi's men shoots him in the chest twice. Luckily, he is wearing a metal breastplate. He is taken to a room where he is tied up, shoved in water, and comes face to face with Uzi. Henry, scared out of his mind, has no idea what is going on. He tells Uzi he has no idea who Edward is, that his name is Henry Spivey and he's never met an Edward before.
As Uzi is preparing to torture Henry, Raymond comes in to rescue him and get "the package." Henry, still unclear on what is happening, takes Raymond's direction and follows him through the building, dodging gunfire. On the way to the extraction point, Raymond removes his mask. Henry, thinking it's Tom, doesn't understand what is going on. Raymond takes a moment to call Tom's wife to let her know he will be back the following day, confusing Henry even more.
Back at Janus, Mavis explains to Henry what has happened. That Edward volunteered to be a part of this program. That Henry Spivey was created 19 years ago, in the Janus corporation, and that Henry is the experiment, not Edward. Since Henry isn't due home until the following day, Mavis takes him to Edward's apartment for the night. There, Henry calls home and asks his wife about the time they met, worried it was all fabricated. Assured it happened as his remembers, he hangs up, satisfied for the moment.
Henry uses the time to search through Edward's apartment and discovers a secret room that he unlocks with his fingerprint. There, Henry finds boxes with information on Edward's past, including the death of his parents and his military record.
Henry finds Edward's keys and takes his Chevy Camaro out for a spin. As he's driving, Edward wakes up and calls Mavis to find out what happened. He makes it known that if Henry spoke to Uzi while in Moscow, he and his family could be in danger. Mavis tells Edward that Henry will be erased the next day. Edward decides to pay Henry's family a visit. His wife wakes up and finds that the person she thinks is Henry, is back home.
After Edward spends a very passionate night with Henry's wife, Henry wakes up in his bed, unsure of how he got there. Downstairs, Angie is making him a very big "thank you" breakfast. Henry then discovers a friendly note on his hand from Edward that reads, "Don't touch my car!! Ever!!!" Henry then realizes that Edward slept with his wife.
Henry steps into the elevator with Tom, or at least that's who he thinks he is. After he slips up and mentions something in passing about Edward's parents, he realizes Tom is actually Raymond. Raymond takes Henry down to Janus, where Tony will erase his memories.
Mavis assures Henry that when he wakes up, he will have forgotten all about Edward and will just be Henry Spivey again. Later that afternoon, Henry returns home to get ready for his son's soccer game. After he changes, he answers the door to find Uzi standing there. Uzi ties Henry up in the kitchen. Henry stands his ground and says that he's never met him before and he doesn't know Edward. Uzi puts a gun to his head. Henry tries to solve the problem by starting with the facts: He is two people.
Henry shows Uzi to his Chevy Traverse. In the trunk he has a GPS device and a shovel. By finding the coordinates in the GPS device, Henry takes Uzi and his man to a location in the desert where Edward must have buried something. In the desert, Uzi tells Henry that he has known Edward for a decade.
Henry passes the case to Uzi, who has his employee open it to be certain it's not booby trapped. However, when Henry reveals that he knows what is in the case, he tells Uzi that although he and Edward can't meet, they do communicate. Henry flicks a button on the GPS device that Edward rigged. Uzi and his mate are blown up with a large blast.
In a flashback: When Henry returns home that afternoon, he opens up a package containing a DVD with a message from Edward, telling him that his and his family's lives are in danger. In the video message, Edward describes where he buried Uzi's package, how he rigged it, and how to use the GPS tracker. Henry returns the package to Mavis, who is shocked to see Henry, not Edward.
Henry takes Mavis' advice to "un-ring any bells" he may have sounded; in his next therapy session with Nora, he lets her know that his dream about Paris was just that, a dream. Henry then leaves a video message for Edward, letting him know that driving someone's car is not the same as sleeping with their wife!