In California, Mister and Mr Livingston have a baby and learn he’s been born with no immunity at all. This means even the weakest germ can kill him, he’ll have to live in isolation, and everything he touches must be decontaminated first. To keep him safe, Jimmy is put inside a plastic bubble where he’ll have to live the rest of his life.
This health issue makes Mr Livingston over-protective of her son, and she doesn’t even take him home until he turns four. When other kids try to meet him, she bursts their balloon to scare them away. She says the world out there is filthy and that he’ll never have to leave the house again.
The Livingstons have prepared the place for him: Jimmy’s room is a big bubble so he can walk freely inside, there’s a decontamination hatch so he can receive food and toys, and there are two pairs of retractable arms so the parents can still be affectionate with their son. Mr Livingston takes good care of him and reads to him every night, but she also keeps him very sheltered. He’s only allowed to read magazines and watch TV that have sanitized content approve by a religious mom.
Mr Livingston also homeschools Jimmy with propaganda so he can be an extreme nationalist like her. Whenever the neighborhood kids come to the front lawn covered in bubble wrap to make fun of him, Mr Livingston scares them away with cold water. Jimmy is only fed his mom’s homemade food, which barely tastes like anything because she disapproves of fat and sugar too.
She also complains when MrLivingston gets Jimmy a bicycle, thinking it could kill him. By the time Jimmy turns sixteen, he’s gifted an electric guitar instead of a car like the other teens. One day Jimmy is looking through the window and sees the new neighbors moving in.
They have a daughter called Chloe and Jimmy instantly falls in love with her. Mr Livingston isn’t happy about this and would indirectly insult Chloe by reading Jimmy stories about boys that die for touching naughty neighbors. Since then, Jimmy pretends to wash the window every day just to look at her.
This helps him reach puberty and he starts to wake up with wood in his pants. The first time he gets scared and hits it with a bat, so his mom has to calm him down and teaches him to repeat the pledge of allegiance until it goes away. Meanwhile Chloe hangs out with friends from school who mock Jimmy and repeat ridiculous rumors about his situation.
She scolds them for it and decides to finally introduce herself. MrLivingston opens the door without a care and Chloe follows the tube system to Jimmy’s room, where he finds him falling out of the decontamination hatch. Jimmy gets nervous when he sees her body up close and calls her the bad word her mother uses, not knowing its real meaning.
Chloe plays along and asks about his guitar, promising to come back tomorrow for another visit. The next Jimmy teaches her how to play guitar using the glove hands on the bubble and recites the pledge every time his body gets too interested. Since then, Chloe starts visiting Jimmy often and they have lots of fun together.
Mr Livingston doesn’t approve but she can’t find a good excuse to stop them. On Jimmy’s birthday, Chloe gifts him a guinea pig inside its own bubble, and for Halloween she brings a bunch of kids and candy so Jimmy can know what the holiday is truly like. The night of Chloe’s birthday, she sneaks into Jimmy’s room while drunk.
Saying she wants a birthday kiss, she tries to enter the bubble, but she passes out in the decontamination chamber. On Chloe’s prom night, she shows Jimmy her wonderful dress and he takes pictures. However he’s devastated to see her leave with her boyfriend Mark, who damages the bubble with his cigarette.
A few nights later, Jimmy looks through the window and discover Mark and Chloe kissing, which breaks his heart. The next day, Mr Livingston reminds him that all women will leave him some day. Sometime later Chloe comes to see Jimmy with big news: Mark has asked her to marry him and the ceremony will happen this weekend at Niagara Falls.
Chloe wants to give Jimmy one last gift before leaving and puts it in the decontamination hatch, but Jimmy is hurt and ignores the box. Instead he gives her the guinea pig back and tells her to leave. Chloe leaves in tears, prompting Jimmy to finally open the gift.
To his shock, he finds a homemade snowglobe with the words “I love you”. Jimmy screams in excitement and finally decides to take control of his life. He designs and builds a smaller version of the bubble that would allow him to leave home, this way he can stop the wedding.
While his parents are sleeping, Jimmy tries to sneak out but falls and rolls downstairs. The noise wakes MrLivingston up but he stays in bed, silently encouraging his son. Once outside, Jimmy is excited over everything: dog poop, the sun, and the fact he can run.
Eventually he reaches the bus station and tries to buy a ticket, but he doesn’t have enough money for it. While trying to think of a new plan, he crosses the road and is hit by a bus. Luckily his bubble saves him.
The people in the bus immediately come to check on him and when they hear of his goal, they agree to take him to Niagara falls and pick him up to get him in the bus. At home, Mr Livingston discovers that Jimmy is gone and screams in panic. She tries calling the police but they don’t take her seriously, so she makes her husband make a fake kidnap note.
However he signs it with “the jews” so it isn’t taken seriously either. The couple decides to go looking for Jimmy themselves and they stop at the bus station, where the clerk tells them about the Niagara Falls plan. Back to the bus, Jimmy notices the group’s uniforms, the lyrics of their songs, how they share the same name, and the things their strange book promotes.
This makes him realize they’re a cult, but calling them that gets the group angry and they kick him out of the bus. Now he’s alone in the middle of the desert and he has to run away from random animals. Eventually he comes across a biker named Slim, who threatens him with his knife.
Jimmy explains he can help him fix his bike. Slim is so grateful that when he hears about Jimmy’s goal, he agrees to give him a ride. He also tells him he used to be in love with a woman named Wildife, who left him for another man.
To this day, Slim wants to find that guy and kill him. Meanwhile the cult finally reunites with their leader, who reveals the big prophecy painted on a rock: the chosen one will come with the holy word inside a living globe. The followers assume that’s Jimmy, so they get back on the road to find him.
That night, Jimmy and Slim make it to Las Vegas and Jimmy is fascinated by all the attractions. He attends his first concert and the crowd tosses him around like a ball. While Slim teaches him how to gamble at the casino, he also tells him what being with a woman is like.
When Jimmy sees that there’s a scooter as a prize, he gambles until he wins it and leaves without Slim because he only has two days left. Soon the Livingstons and the cult make it to Las Vegas too. As soon as Slim sees the cult members, he remembers they left Jimmy in the desert and threatens to kill them.
In return the cult bus runs over his bike. A few hours later, the Livingstons reach the road and see Jimmy on the scooter. Mr Livingston forces her husband to turn the car and block the way, accidentally hitting the scooter in the process.
Jimmy flies out and his bubble makes him bounce off for a while until he lands inside a train. He screams when he sees the people inside and learns that they’re part of a freak show handled by Doctor Phreak, who owns these people like slaves. Suddenly the train stops and Jimmy bounces out, finding Doctor Phreak waiting.
Jimmy laughs at his size and Doctor Phreak starts furiously breaking a car’s windows as a threat. However when he hears that Jimmy is “the bubble boy”, he thinks he could be part of his show. When Jimmy says no, Phreak jumps on the bubble and tells him that no woman would ever love a weirdo.
An offended Jimmy pushes him off and the bouncing sends Phreak flying, causing his small body to hit a huge truck. Then Jimmy gets ready to leave and the other freaks try to follow him, so he explains to them they’re now free and they can do whatever they want, but he must finish his mission alone. Next Jimmy takes a handcar to advance through the train tracks, but it’s too slow so he stops at a restaurant to ask for help.
He finds a sheriff and a bunch of rednecks mocking a man called Pushpop and Jimmy comes to his defense. The men start mocking him instead, but when they hear he’s got not immunity, they think it’s some disease and everyone starts running away, leaving Jimmy inside. When they slam the door, a lamp falls and starts a fire in the restaurant.
Jimmy panics as he tries to find an exit, thankfully Pushpop appears on the backdoor and takes Jimmy away in his ice-cream and curry truck. His driving is crazy and Jimmy almost falls, but at least they get away before the restaurant explodes. Meanwhile the Livingstons reach the train and ask Phreak about Jimmy.
Mr Livingston treats Phreak like a baby, offering to pay the information with candy. In the end Mr Livingston calls Chloe and tells her to stay away from her son, insulting her without hesitation. While they’re distracted, the other freaks steal the Livingstons’ car.
Since Phreak wants his group back, he steals a truck and agrees to leave with the couple. Back to Jimmy, he shares his goal with Pushpop, who agrees to take him to Niagara Falls. Jimmy falls asleep during the trip and has a weird dream about Chloe being attack by dinosaurs.
He tries to save her, but the dinosaurs defeat him and Mark saves Chloe instead. Jimmy wakes up screaming and startles Pushpop, causing him to accidentally hit a cow in the middle of the road. This greatly upsets him because cows are sacred in his religion, but Jimmy quotes his mom saying all other religions are lies.
Offended, Pushpop tells Jimmy to go away while he stays to do a ritual for the cow’s death. Jimmy gets going while tasting ice-cream for the first time. Minutes later, a truck drives by and crushes the cow even more.
Soon Slim also appears with a whole gang of bikers and they ask Pushpop about the cult. While waiting they have Pushpop’s ice-cream and watch in surprise how the cult bus shows up to driver over their bikes. Luckily Pushpop agrees to give the gang a ride.
Meanwhile Chloe is trying on her wedding dress but she’s having doubts because she can’t stop thinking about Jimmy. In the evening, Jimmy manages to reach a town and asks Pappy for a ride, but he must pay five hundred dollars. Obviously he doesn’t have that money, but he sees a sign advertising a cash prize and enters the building.
It turns out to be a naughty club, where he agrees to fight in the mud with two gorgeous women. Because of the bubble, the women keep slipping off and can’t hurt him, so Jimmy easily wins the fight while he keeps reciting the pledge. With the money in hand, Jimmy comes out to look for Pappy, only to find the cult bus instead.
The cultists immediately kidnap him, which is seen by the freaks that just arrived. Jimmy is taken to the ritual spot, where the cultists get read to free him from his bubble. While everyone prays, the freaks steal some uniforms and try to save Jimmy, but when the cultists see them they think the ritual failed and everyone is mutating.
Everyone panics and the freaks use the distraction to move Jimmy away, only to find the way blocked by Slim and the gang. A crazy fight ensues among the bikers, the freaks, and the cultists, during which Jimmy runs to pay Pappy so they can finally drive off. While everyone runs back to their vehicles to continue the chase, Jimmy falls asleep in the car.
The next morning, he’s shocked to discover Pappy died while still driving. The car loses control and a sudden turn sends Jimmy flying right through a sign by the road. The car continues without him so Jimmy decides to enter a grocery store to call Chloe.
Unfortunately Mark picks up and tells Jimmy to give up because they’re getting married in an hour. Losing all hope, Jimmy calls his mom to ask her to pick him up. An excited Mr Livingston throws Phreak out of the car because she doesn’t need him anymore.
While waiting, a crying Jimmy tells the girl at the counter if he can have a beer for free, and the girl agrees. Jimmy can’t tell she isn’t the real clerk, she’s a robber who is keeping the actual employee hidden outside the counter. As soon as Jimmy takes his first sip of beer he passes out.
Eventually his parents find him and get him in the car, but before leaving Mr Livingston must go to the bathroom. Jimmy and his dad use this time alone to finally bond, and it’s clear that MrLivingston is jealous that Jimmy got to have fun. He uses a moon metaphor to tell his son to never give up, and Jimmy runs away.
Mr Livingston freaks out when she notices and makes her husband chase after their son. Soon the other three groups show up as well, screaming at each other over Jimmy. The chase takes them to an airport, where an airplane is about to take off.
Jimmy climbs on it and gets to escape just in time, laughing when he sees the pilot is Pappy’s twin brother Pippy. The sudden take-off causes the four vehicles to crash against each other and Slim is shocked to see that Mr Livingston is his ex-girlfriend Wildfire. Moments later the plane makes it to Niagara Falls at the same time the wedding ceremony is starting.
The plane starts malfunctioning so Pippy has to pull off a crazy move to avoid crashing, however it causes Jimmy to fall off and land in the water. Remembering everything Slim taught him, Jimmy lets the waterfall guides his way as he floats in his bubble. In the church, Mark says “I do” but Chloe hesitates.
At that moment Jimmy bursts in and shocks Chloe by coming out of his bubble, saying he’d rather have a minute with her than a whole life alone. Then he kisses Chloe and tells her he loves her before collapsing. Chloe thinks he’s dead as the Livingstons arrive with all the other groups.
Mr Livingston cries for her dead son, but her husband is done and forces her to confess the truth: Jimmy isn’t sick anymore. He got better when he turned four, that’s why they took him home from the hospital that year. Mr Livingston has been lying to him to keep him in the house forever.
Jimmy wakes up and is so happy to have a chance at life that he forgive his mother, then he finally gets together with Chloe. Sometime later, Jimmy and Chloe get married and all the friends Jimmy made during his adventure attend. Pushpop has brought the cake and a cow, he also reveals the cultists are now following his beliefs.
Slim has befriended the Livingstons and they’re in a poly relationship. When the happy couple gets ready to leave, they discover their drivers are the old twins, who have found the woman they used to fight over.
