Teenaged brothers Zach and Gray Mitchell visit Jurassic World, a dinosaur theme park at the original Jurassic Park site on Isla Nublar of which their aunt Claire Dearing is the operations manager. Claire assigns her assistant as the boys' guide but they evade her and explore on their own. Elsewhere on the island, U.S. Navy veteran and ethologist Owen Grady has been training four Velociraptors and researching their intelligence. Based on the raptors' ability to follow commands, Vic Hoskins, the head of InGen Security, believes the animals can be weaponized, an idea Owen and his assistant Barry strongly oppose.
Prior to its opening, Claire and park owner Simon Masrani inspect the park's newest attraction Indominus rex, a genetically-engineered dinosaur created by geneticist Dr. Henry Wu. Masrani tasks Owen with evaluating the enclosure. Owen warns Claire the Indominus lacks social skills, making it dangerous and unpredictable. When it appears the Indominus has escaped, Owen and two park workers enter the enclosure. The Indominus, which can camouflage itself and mask its heat signature, suddenly appears. Owen survives the attack, but it kills the other two men before escaping into the island's interior. Owen tells Masrani to have the Indominus killed; to protect his company's investment, however, Masrani dispatches a specialized unit to subdue it with non-lethal weaponry. After most of the unit is wiped out, Claire orders the evacuation of the island's northern sector.
While exploring the park in a vehicle, Zach and Gray enter a restricted area. The Indominus arrives and destroys the vehicle but the boys escape. They find the ruins of the original Jurassic Park facility, repair an old Jeep Wrangler, and drive back to the park resort. As Claire and Owen search for the boys, they barely escape the Indominus. Masrani and two troopers hunt the Indominus by helicopter but it breaks into the park's aviary, releasing pterosaurs – Pteranodon and Dimorphodon species – which collide with the helicopter, causing it to crash. Gray and Zach find Owen and Claire at the resort as armed personnel shoot down swarming pterosaurs with tranquilizers.
Assuming command, Hoskins orders that the raptors be used to track the Indominus; Owen, forced to comply, leads the raptors. They find the Indominus and the animals begin communicating among themselves. Owen realizes the Indominus has Velociraptor DNA; it becomes the pack's new alpha, usurping Owen's dominance. Troops fire on the Indominus but it escapes. The raptors kill most of the troops, but one raptor is killed. Hoskins evacuates Wu and the dinosaur embryos from the island to protect Wu's research. Owen, Claire, and the boys find Hoskins at the lab but a raptor breaks in and kills him.
Owen re-establishes his bond with the three raptors before the Indominus reappears. They attack the Indominus but two are killed. Claire releases the park's veteran Tyrannosaurus rex and lures it into a battle with the Indominus, which gains the advantage over the aging T-Rex until Blue, the only surviving raptor, joins the fight. Overwhelmed, the Indominus is cornered at the lagoon's edge, where it is dragged underwater by the Mosasaurus. The survivors are evacuated and the island is abandoned again. Zach and Gray are reunited with their parents; Owen and Claire decide to stay together.