In 1996, in Brantford, New Hampshire, teenager Alex Vreeke receives the Jumanji board game, found by his father on a beach. When Alex dismisses it, the game transforms into a video game cartridge. When he plays it, he is sucked into the game.
Twenty years later, four students in Brantford High School are placed in detention together: Spencer Gilpin, who is writing essays for his former friend, Anthony “Fridge” Johnson (who is also in detention), and Bethany Walker and Martha Kaply have both disrespected their respective teachers during class. Assigned to clear out the school’s basement, the four find Jumanji, now a five-player action-adventure console game. With one of the playable characters (video game avatars) inaccessible, the teens select the others, and are sucked into the game.
They find themselves in a jungle, each now in the forms of their game avatars. Spencer is a tough, muscular explorer named Dr. Smolder Bravestone, Fridge is a short zoologist named Franklin “Mouse” Finbar (whom he had selected upon misreading the name as “Moose”), Martha is a gorgeous commando and martial art expert named Ruby Roundhouse, and Bethany is an overweight, male cartographer named Professor Sheldon “Shelly” Oberon. They soon realize that they are in a video game, and each have three lives. If they lose all three, they will actually die. Each of their avatars also comes with special skills and weaknesses.
They learn from Nigel, an NPC, that the big-game hunter, Van Pelt, wants to obtain a jewel, the “Jaguar’s Eye”, allowing him to manipulate Jumanji’s animals. To escape the game, the players must return it to an enormous jaguar statue and call out “Jumanji”. Along the way, the group begins to lose lives through various means. The group start working together to obtain a clue from a snake but are captured by Van Pelt’s men. They are rescued by Alex, the fifth player, whose avatar is a pilot named Seaplane McDonough. Recuperating in a treehouse built by previous player Alan Parrish, Alex learns that he has been in the game for twenty years. They commandeer a helicopter and fly for the jaguar statue to return the jewel.
Arriving at the statue, the players find themselves facing Van Pelt’s forces and jaguar guards. Using their resources and teamwork, the players distract the villains while Spencer returns the jewel to the statue and cries out “Jumanji!” The game ends, disintegrating Van Pelt, and the teens reverted back to their former selves and returned to the real world, but discover that Alex did not come with them. On their way home, they reveal that the Vreeke household – once abandoned with Alex’s disappearance – has been restored. An adult Alex appears; he emerged in 1996, and history was changed. He is now married, and named his newborn daughter after Bethany in gratitude of saving his life before leaving Jumanji.
Spencer and Fridge reconcile, Bethany becomes a better person and makes plans to go backpacking from her experiences in the game, and Martha starts dating Spencer. The four hear Jumanji’s drumbeats, but they take the game behind the school, and seemingly destroy it with the bowling ball they found in detention.