In the New Mexico desert, Admiral Al Calavicci is driving down the road when he sees an attractive woman in a pink dress at the side of the road. He stops and says he'd like to fix her flat, but he needs to be on his way. He offers her a lift and as they drive, the woman, Tina, notices an odd aurora effect on the skyline. Al tries to dismiss it as sheet lightning but Tina notes that it's the location of the first atomic bomb, and some people claim there's still a secret military project there.
Al opens up a communication channel and a man named Gooshie tells him that Sam is leaping. Al warns that they're not ready but Gooshie says it's too late and Sam is in the accelerator. In the chamber, a man in a white suit is enveloped in energy as he smiles in triumph. Al tells Gooshie not interfere and then accelerates toward the lights.
At a house in the desert, an alarm clock goes off at 5 a.m. and Sam Beckett wakes up. He realizes that they did it, but then can't remember what it is they did… or anything else. A pregnant woman wakes up in bed next to him and calls him Tom, and goes to put the coffee on. She kisses Sam, who has no idea who she is. The woman, Peggy tells Sam that Bird Dog will be there to pick him up. She gets Sam into the shower, and he forgets to take off his boxers. Sam figures that he's dreaming and decides to go with it. He starts shaving and looks in the mirror, and sees someone else's face.
Peggy hears Sam's startled gasp and comes in, but doesn’t see anything unusual. Their son Mike comes in to say that Captain "Bird Dog" Birdell is calling, and Sam is surprised to see that he has a son as well. Peggy wonders if Sam is sick, but Sam remembers an office and calls a phone number for his office. Peggy points out that he's not dialing enough numbers, and has no idea what an area code is. The Howdy Doody Show
is playing on the TV. Sam walks outside and finds himself in military tract housing, and a jet flies overhead. He accepts that he's not dreaming… but he's trapped in a nightmare.
Sam decides to go along. According to everyone else, he's Air Force Captain Tom Stratton and the year is 1956. His best friend is Bird Dog. Bird Dog drives them to work but pulls over to hit on a woman going into a diner. Bird Dog tries to flirt with her and says he'll meet her at the ranch later, and boasts he and Sam are the only ones brave enough to fly the X-2. She mentions Captain Tony LaMotta, another pilot, who Bird Dog dismisses. Sam suggests that he might not remember how to fly but Bird Dog thinks he's playing a joke and suggests they play it on their flight doctor, Weird Ernie.
At base, Weird Ernie takes their claim seriously and warns that they've rewired the insulation after the fire warning light went off during Tom's last test flight. He tells them to shut down if the light comes on again. Sam notices a man in a gaudy tuxedo standing in the office. The man, Al Calavicci, boasts about how Bird Dog reminds him of himself in the early days. As the pilots leave, Al tries to talk to Sam, who ignores him.
At home, Peggy talks to her friends and asks for their opinion on her stretch marks. As the planes lift off, the women notice and Peggy admits that she's jumpy.
Sam rides co-pilot while Bird Dog flies the bomber that is lifting the X-2 to the point where Captain LaMotta will begin the test flight. Sam is just starting to relax when Bird Dog tells him to take over while he answers a call from Mother Nature. The plane begins to tilt and Sam has no idea what to do. Weird Ernie calls on the radio and asks if something is going on. Bird Dog comes back to the cabin and levels off the plane. He makes an excuse and then tells Sam to save his joke for Weird Ernie.
At home, Peggy is pouring coffee as the house vibrates again. She looks nervously up at the sky and realizes that the test flight should begin any time.
Bird Dog brings the plane up and prepares to drop the X-2. Al appears in the back and waves to Sam, and Sam asks if everyone is strapped in. Bird Dog doesn't appear to see Al. They release the X-2, which breaks the sound barrier and accelerates. LaMotta begins his test run and assures them that the fire warning light. He hears a bubbling noise and then the warning light goes off. He switches off the rockets and the alarm shuts down. However, when he starts to turn, the X-2 goes out of control and then explodes in mid-air. At home, Peggy and the other wives run out and see LaMotta parachuting to safety.
Later, the men are celebrating at the local bar and LaMotta is dancing with the woman from earlier. Bird Dog cuts in while Sam relaxes with Peggy, who he finds beautiful despite her pregnancy. He asks her to dance and she hesitantly accepts. Al comes in, wearing a tux and enjoying the ambience, while Peggy wonders how Sam has suddenly become such a good dancer. Sam notices Al and asks Peggy who he is, but she can't see a man in a tuxedo. Sam has Peggy sit down and then goes to the jukebox where Al is standing. He asks if he's dead and Al laughs, addressing him by name. Al soon realizes that Sam has amnesia and doesn't recognize him, or remember the experiment. Bird Dog notices him talking to thin air and figures he's practicing his practical joke. Al disappears and Sam goes outside to see him walking, across the parking lot. He follows Al, who walks through an invisible door and disappears.
As Sam and Peggy drive home, Peggy admits that the night out was fun and notes that he didn't talk flying or drink heavily, and comments that he was talking at the juke box. However, she soon starts to realize something is wrong and Sam tries to explain that his name isn't Tom, but he can't remember what his last name is and has no idea who Peggy and the others are. Peggy refuses to believe him and tells him to stop. He apologizes and claims he's setting up a gag.
The next morning, Sam wakes up early from a dream of flying and recalls that he was raised on a dairy farm in Indiana. He focuses on that and remembers his sister Kate, who married a naval officer, Lt. Jim Bonick. His mother lives with them and his father died in 1974. His father is alive right now. Sam goes to the phone but can't remember the number or his family name. Mikey comes out and asks what's wrong, and reminds him that they have a fishing trip planned.
As they fish, Sam goes off into the brush to free his line and finds Al, wearing a bathrobe and complaining about a hangover. Sam reaches for him and finds that his hand goes right through him. Al says that he'll explain as best he can, but Sam can't ask any questions. He explains that he's a neurological hologram that only Sam can see and hear. Sam starts to recall the theory, but has no idea how he knows it. Al then explains that they interface with the help of Ziggy, a hybrid neurological computer. Sam realizes the technology doesn't exist in 1956, and Al says that he's not from that time. When Sam demands more answers, Al admits he's limited in what he can explain. He admits that the experiment went a little "caca" due to technical difficulties, and can't retrieve him. Al says they tried to retrieve him that morning but failed, and asks if Sam told anyone he's not Tom Stratton. Sam admits that he told Peggy, and Al explains recovery is dependent on everyone believing he is who he appears to be. He also explains that Tom is with them, and he's suffering from partial amnesia. When Al explains they're going to try to retrieve him again on Tuesday, Sam tells him he's scheduled to fly the X-2 on Monday.
Later, the pilots and their wives are having a barbeque and a jet passes overhead and then does a roll and flip. Everyone except Peggy is impressed. As she goes inside, Sam goes after her but Peggy insists that she's fine. She's surprised that Sam is spending so much time with Mikey. As Sam goes, Peggy passionately kisses him and Sam kisses her back. As he goes, she senses something different about his kiss.