The Terrible Thing that Happened to Barnaby Brocket

Alistair and Eleanor Brocket, a couple living in Sydney, Australia, value normalcy above all else. Their shared obsession stems from their own childhoods. Alistair’s parents, who were failed actors, forced him into a traumatic stage career that ended with a disastrous performance. Eleanor’s mother pushed her through a grueling circuit of child beauty pageants, which she despised. They meet at a law firm, marry, and have two perfectly normal children, Henry and Melanie, creating the ordinary life they crave.

Their world is disrupted by the birth of their third child, Barnaby. Immediately after he is born, Barnaby defies gravity and floats to the ceiling of the delivery room. His parents are horrified by this abnormality. To manage his condition at home, Alistair nails mattresses to the ceilings to prevent Barnaby from injuring himself. Their neighbor’s comment, “That’s not normal, that,” reduces Eleanor to tears. For the next four years, Barnaby’s parents keep him mostly hidden at home to avoid public embarrassment. When forced to take him for a walk, Eleanor attaches a dog leash to a collar around his neck, turning him into a human kite. The walk ends in humiliation when they are gawked at by neighbors, and Eleanor tells Barnaby she does not like who he is.

At age eight, Barnaby is sent to the Graveling Academy for Unwanted Children, where he is tied to his chair daily. He befriends Liam McGonagall, a boy with hooks for hands. Soon after, Eleanor forces Barnaby to wear a heavy rucksack filled with sandbags to keep him grounded. Later, on a school trip to climb the Sydney Harbour Bridge, Barnaby is revealed to be the ten millionth climber. During the ensuing press conference, he floats to the ceiling, creating a media frenzy that mortifies his parents. They tell him they will no longer tolerate his difference.

After the media attention subsides, Eleanor and Alistair enact a secret plan. Eleanor takes Barnaby for a walk to Mrs. Macquarie’s Chair in the Botanic Gardens. There, she uses scissors to cut a hole in his rucksack, letting the sand pour out. As the bag empties, Barnaby begins to float away. He cries for help, but Eleanor waves goodbye, telling him it is for the best as he rises uncontrollably into the sky. Back home, Alistair and Eleanor throw away the postcards Barnaby sends from his travels, telling Henry and Melanie that Barnaby floated away because he willfully removed his rucksack. The older siblings eventually find a postcard and grow suspicious.

High above Australia, Barnaby is rescued by Ethel and Marjorie, two elderly women in a hot-air balloon who were also disowned by their families for not being "normal." Unable to fly against the wind, they take him to their coffee farm in Brazil. There, Barnaby meets a young woman named Palmira. Ethel and Marjorie arrange for his travel home, and he boards the Fonseca Express train, which travels from São Paulo to New York. He falls asleep and misses his stop in Rio de Janeiro, waking up at the end of the line in New York City. A thief steals his rucksack, and he floats up the side of the Chrysler Building, where he is rescued by Joshua Pruitt, a struggling artist estranged from his family. To repay him, Barnaby helps get Joshua’s art discovered by a famous gallery owner, launching his career.

A Canadian art critic, Charles Etheridge, is so impressed by Joshua's work that he buys Barnaby a train ticket to Toronto. On the journey, Charles reveals that his own family, obsessed with physical beauty, abandoned him after he was disfigured in a fire as a child. In Toronto, Barnaby is kicked out of a taxi and wanders into a football stadium, where he accidentally floats away during a game. He is rescued and then kidnapped by the sinister Captain Elias Hoseason, who forces him into a traveling circus called "Freakitude," where he is reunited with his old friend Liam McGonagall and meets other individuals with unique physical traits.

The circus travels by ship to Dublin, Ireland, where the group is freed by Stanley Grout, a wealthy, dying man fulfilling a wish list of adventures before he dies. Stanley takes Barnaby to Africa, where they attempt bungee jumping and parachuting, both of which fail for Barnaby due to his floating. While they are camping under the stars, a fox chews through the parachute Barnaby is using as a weight, and he floats away from Earth into "middle space."

He is rescued by the international crew of the spaceship Zéla IV-19. Inside the pressurized cabin, Barnaby discovers he does not float. The astronauts share their own stories of being rejected by their families for choosing unconventional careers. During a space walk, an astronaut’s tether snaps, and Barnaby volunteers for the rescue, saving his life. The spaceship’s mission ends, and it lands just outside Sydney.

Mistaken for an alien, Barnaby is quarantined before being sent to a hospital. A doctor, Dr. Washington, discovers the cause of his condition: a rare imbalance in his inner ear canals makes his brain misinterpret gravity, causing him to "fall up." She explains that a simple operation can correct the issue and make him "normal." Alistair and Eleanor visit and are overjoyed, telling Barnaby he can only come home if he agrees to the surgery. Henry and Melanie also visit, smuggling in the family dog, Captain W. E. Johns.

Reflecting on his incredible journey and the many "different" people he met, Barnaby realizes he does not want to be normal and likes who he is. Just before he is taken for the operation, he presses a button to open the skylight in his room. He unbuckles the strap holding him to the bed and begins to float. Captain W. E. Johns leaps onto his legs, refusing to be left behind again. Together, Barnaby and his dog float out of the hospital and into the Sydney night sky, ready for new adventures.