In 1869, two brothers bury a chest, hoping that nobody ever finds it. In 1969, 12-year-old Alan Parrish (whom Brian is hanging out with) visits a shoe factory owned by his father, Samuel Parrish. He meets Carl Bentley, an employee, who shows off a new shoe prototype he made by himself. After Alan misplaces the shoe and damages an important machine, Carl takes the blame and loses his job. After being attacked by several bullies, who steal his bicycle, Alan follows the sound of tribal drumbeats to a construction site. He finds a chest containing a board game called Jumanji, and brings the game home.
At home, after an argument with Samuel about attending a boarding school, Alan plans to run away. Sarah Whittle, his friend, arrives to return his bicycle, and they begin playing Jumanji. With each roll of the dice, the player' piece moves by itself and a cryptic message describing the roll's outcome appears in the crystal ball at the center of the board. After Alan's first roll, a message tells him and Brian to wait in a jungle until someone rolls 5 or 8, and he and Brian are sucked into the crystal ball. Sarah rolls the dice, and a swarm of bats appears and chases her out of the house.
In 1995, after their parents died in an accident, Judy and Peter Shepherd (whom the rest of the team, the Griffin Family, Little Bear, and his friends are with) move into the vacant Parrish house with their Aunt Nora. Judy, Peter, and the team find Jumanji in the attic and begin playing it. Their rolls summon giant mosquitoes to attack, then a group of monkeys. The game states that everything will be restored when the game ends, so they continue playing. Peter's next roll releases both a lion and an adult Alan and even Brian himself. Alan locks the lion in a bedroom and heads to his father's factory. On the way, he meets Carl, who works as a police officer. In the now abandoned factory, a homeless man tells Alan that after his disappearance, Samuel abandoned the business and dedicated everything to search for his son, until his death four years earlier. The factory's closure has devastated the town's economy.
Alan realizes they need Sarah to finish the game, and the three managed to find the distraught Sarah and convince her to join them. Sarah's move releases fast-growing man-eating vines, and Alan's next roll releases a big game hunter named Van Pelt, who has been hunting Alan and Brian in the jungle, and the game also summons Team Galactic who were trying to kill Brian in the jungle too. The next roll summons a herd of various animals, causing a stampede, and a pelican steals the game. Peter gets it back, but Alan and Brian are arrested by Carl, and Van Pelt and Team Galactic take the game. Our heroes, Peter, Sarah, and Judy follow Van Pelt and Team Galactic to a department store where they set booby traps to subdue them and take back the game, while Alan and Brian escape from Carl's car. When the group return to the mansion — now completely overrun by jungle wildlife — they release one calamity after another, until an earthquake destroys the mansion. As Van Pelt and Team Galactic corner Brian and Alan and prepare to kill them, Alan makes the winning roll, causing everything that has happened as a result of the game to be reversed.
Back in 1969, Alan and Sarah are children once again, but have full memories of the game's events. Alan reconciles with his father and admits that he damaged the factory's machine. Carl is rehired, and Sam tells his son that he does not have to attend boarding school. Alan and Sarah throw Jumanji into a river, then share a kiss.
In the present day, Alan has taken over his father's business. Alan and Sarah are married and expecting their first child. They meet Judy, Peter, and their parents Jim and Martha for the first time at a Christmas party. Alan offers Jim a job, and convinces them to cancel their upcoming ski trip to Canada, preventing their deaths.
On a beach in France, two young girls hear drumbeats while walking, as Jumanji lies buried in the sand.
- Peter Griffin, Lois Griffin, Meg Griffin, Chris Griffin, Stewie Griffin, Little Bear, Duck, Owl, Cat, Hen, Emily, and Lucy guest star in this film.
- Team Galactic (Mars, Jupiter and Saturn) will work for Van Pelt in this film.
- The film will be dedicated in memory of Robin Williams, who committed suicide on August 11, 2014, and James Horner, who died in a plane crash on June 22, 2015.
- The end credits song for this film will be an instrumental version of "Be Prepared".
- 1969/Mr. Parish's shoe factory
- Brian meets Alan/Alan and Brian discover Jumanji
- At the Parish's/Alan and Sam's argument
- 26 years later/The Shepherds move in
- A haunted rumor
- Back in the game/Mosquitos and Monkeys
- The Lion attacks!/Alan and Brian return
- Searching for Alan's parents
- Mosquitos again!/Reserve psychology
- It's not my turn/Madame Serena is Sarah Whittle
- Crawling vines and plants/I won't stop playing
- Van Pelt & Team Galactic!
- Peter saves the game/Carl arrests Alan and Brian/Peter cheats
- Panic town/Sir-Save-A-Lot
- To the rescue/Peter grows a tail
- Monsoon/Crocodile attack!
- The Earthquake/Alan wins
- Back in 1969/Alan makes up with Sam
- Burial at sea/Reunion in 1995/Ending