Two decades after the events at Jurassic Park, a new theme park, Jurassic World, now operates in Isla Nublar, off the Pacific coast of Central America. This new park is run by the Masrani Global Corporation, which also owns InGen, the genetics company that creates the dinosaurs. Brothers Zach and Gray Mitchell are sent to visit their aunt, Claire, Jurassic World's operations manager. Claire's assistant greets them as she is too busy recruiting corporate sponsors.
Trois ans après les événements du parc Jurassic World, les dinosaures, redevenus les maîtres d'Isla Nublar, se retrouvent soudainement menacés d'extinction lorsque le volcan de l'île, jusque là endormi, s'apprête à entrer en éruption. L'ancienne dirigeante du parc Claire Dearing, qui préside dorénavant une association pour la protection des dinosaures, se bat pour sauver les derniers dinosaures de la planète. Tout le monde lui tourne le dos jusqu'à ce qu'un dénommé Benjamin Lockwood, ancien collègue et ami de John Hammond, la contacte pour soutenir son projet. Celui-ci lui propose d'aller sauver les animaux piégés sur Nublar et de les amener dans un « sanctuaire » spécialement créé pour les protéger, loin des humains.
Sixty-five million years ago, the alien race known as the "Creators" invade Earth, wiping out most of life on the planet including the dinosaurs with the "Seeds", and cyber-form thousands of planets, including Cybertron. In the present, Darcy Tirrel discovered frozen dinosaur corpses in the Arctic.
John Hammond, the founder and CEO of bioengineering company InGen, has created a theme park called Jurassic Park on Isla Nublar, a tropical island populated with cloned dinosaurs. After a park worker is killed by a Velociraptor, the park's investors, represented by lawyer Donald Gennaro, demand that experts visit the park and certify it as safe. Gennaro invites the mathematician Ian Malcolm while Hammond invites paleontologist Dr. Alan Grant and paleobotanist Dr. Ellie Sattler. Upon arrival, the group is stunned to see three Brachiosaurus and a herd of Parasaurolophus in the distance.
Ellie and Manny are expecting their first child, and Manny is obsessed with making life perfect and safe for the family, since his first experiences as a husband and father went bad when his family were killed by hunters. At the same time, Diego finds himself unable to catch a cocky gazelle he has been stalking and decides to leave the herd, believing that he is losing his predatory nature as a tiger. Sid grows jealous of Manny and Ellie and “adopts” three apparently abandoned eggs that he finds in an icy underground cavern and call them Egbert, Shelly, and Yoko. Manny tells him to put them back, but Sid instead looks after the eggs, which hatch into baby Tyrannosaurus the next morning.
In the opening scene, Scrat, the saber-toothed squirrel climbs a glacier to bury his acorn, but accidentally opens a hole in it, causing water to spurt out. The world of ice is slowly melting. The creatures of the Ice Age are all shown enjoying themselves on slides and pools made by the melting ice; among them the three protagonists of the first film: Manny, Sid, and Diego. Sid opens a small day camp, where none of the younger creatures take him seriously, nor do Manny and Diego, which leaves Sid seeking a daring deed. Fast Tony, a local con artist is claiming that the earth will flood and that the bark and reeds which he sells are needed to stay alive. Manny dismisses the idea, but is distracted when he sees that Sid will try to high dive from a giant waterfall; as Manny goes with Diego to the top of the waterfall to save Sid from his act of daredevilry, suddenly the ice under Diego's feet was breaking, causing him to bolt in fear, this also made Sid figure that Diego is afraid of the water. The herd figure that the pleasant weather has caused the ice shelves to melt, and it is kept from destroying the valley only by the glaciers, which have formed a dam.
Four years after the disaster at Jurassic Park, the wealthy Bowman family makes an excursion to the island of Isla Sorna during a yachting cruise. Their young daughter wanders off and is attacked by a pack of Compsognathus, but survives. The incident allows Peter Ludlow, John Hammond's nephew, to gain control of his uncle's company InGen, which is in severe financial straits after the events at Jurassic Park. Hammond contacts Ian Malcolm and explains that Isla Sorna is the island where the dinosaurs were engineered and nurtured before being moved to Isla Nublar, Jurassic Park's location. He also explains that after the park was shut down, Isla Sorna was abandoned during a hurricane and the dinosaurs left to survive in the wild, where they have been inexplicably thriving. Hammond asks Malcolm to join a team that will travel to Isla Sorna to document the dinosaurs in order to rally public support against human interference on the island. Ian initially declines but, after learning that his girlfriend, paleontologist Sarah Harding, is part of the team and is already on the island, he agrees to go.
In 1933, at the height of the Great Depression, New York City vaudeville actress Ann Darrow has lost her job and is hired by financially troubled filmmaker Carl Denham to star in his new film. Ann signs on when she learns her favorite playwright, Jack Driscoll, is the screenwriter. As their tramp steamer, the SS Venture, makes the lengthy journey to the remote and mysterious Skull Island, Ann and Jack fall in love. Captain Englehorn begins having second thoughts about the voyage, prompted by crew speculation of trouble ahead.
In 1954, a nuclear bomb is detonated at the moment a giant creature emerges from the ocean. In 1999, Project Monarch scientists Ishiro Serizawa and Vivienne Graham investigate a colossal skeleton unearthed in a collapsed mine in the Philippines. They find two spores; one dormant and one hatched that made a trail into the sea. In Japan, the Janjira Nuclear Power Plant experiences unusual seismic activity and Supervisor Joe Brody sends his wife Sandra and a team of technicians into the reactor. A tremor breaches the reactor, leaving Sandra and her team unable to escape while the plant collapses.
Suneo shows everyone a fossilized claw of a Tyrannosaurus rex and Nobita is angry that he doesn't get a look. Nobita claims that he will be able to find a living dinosaur. Panicking, Nobita researches on dinosaurs and starts digging in a hill. But then, a landlord shouts at him and makes him dig a hole in the ground to dispose of some egg shells. Nobita unearths a rock shaped like an egg. Using the time-wrap, he returns the rock into its former form and plans to hatch the egg. He spends a day and night wrapped tightly in a blanket with it on his futon, despite it being the peak of summer. A "Futabasaurus" comes out, and Nobita decides to name the plesiosaur Piisuke. Suneo and Gian come looking for Nobita but because Piisuke is still too small, Nobita doesn't show them the plesiosaur and instead makes a deal with them. If he cannot show them a real dinosaur, he would have to eat spaghetti through his nose. Meanwhile, Nobita and Piisuke form a strong bond between them with Nobita working very hard to make sure the baby plesiosaur is well looked after, feeding it his own dinner of sashimi and playing with it. He grows very attached to Piisuke.
Scrat va dans l'espace et provoque la collision entre deux planètes, ce qui crée un astéroïde filant droit vers la Terre. Manny, Sid, Diego et le reste de la bande vont devoir fuir leur chez-soi. Buck, la belette de L'Âge de glace 3, est de retour. Nos héros vont voyager vers des terres exotiques et rencontreront une ribambelle de personnages hauts en couleurs, tels que le spirituel Shangri Lama.
L'agence crypto-zoologique Monarch déploie de nombreux moyens pour combattre des créatures de tailles divines, appelées Titans. Ces derniers réapparaissent petit à petit des entrailles de la terre. La paléobiologiste Emma Russell, travaillant pour Monarch, a été traumatisée par la mort de son fils Andrew en 2014. Elle a mis au point l'Orca, jadis imaginé avec son ex-mari Mark, une machine qui permet de capter et reproduire les signaux émis par les Titans. Son invention attire des convoitises. Emma entraine avec elle sa fille Madison. Son père, Mark va tout faire pour retrouver sa fille, tout en tentant de survivre dans un monde envahi de monstres. Godzilla va ainsi devoir compter sur une alliée, le papillon géant Mothra pour affronter les 2 menaces que représentent le ptérosaure super-rapide Rodan, ainsi que son pire ennemi, le dragon à trois têtes King Ghidorah, qui est l'Alpha des Titans. Ces anciennes super-espèces veulent toutes la suprématie et mettent en danger la survie de l'humanité. Alors qu'un combat apocalyptique se prépare, Godzilla, seul prétendant au titre capable de rivaliser avec l'Alpha, aidé des humains, devra s'imposer et ainsi affirmer sa place en tant que roi des monstres.
A saber-toothed squirrel (known as Scrat) is trying to find a place to store his prized acorn. Eventually, as he tries to stomp it into the ground, he causes a large crack in the ground that extends for miles and miles and sets off a large avalanche. He barely escapes, but finds himself stepped on by a herd of prehistoric animals. The animals are trying to avoid the ice age by migrating south. Sid, a clumsy ground sloth left behind by his family, decides to move on by himself but is attacked by two Brontops whom he angered. Sid is soon saved by Manfred ("Manny"), an agitated mammoth who fights them off and is heading north. Not wanting to be alone and unprotected, Sid follows Manny. Meanwhile, Soto, the leader of a Smilodon pride, wants revenge on a group of humans by eating the chief's baby son, Roshan, alive. Soto leads a raid on the human camp, during which Roshan's mother is separated from the rest and jumps down a waterfall when cornered by Soto's lieutenant, Diego. For his failure, Diego is sent to find and retrieve the baby.
Following a nuclear test in French Polynesia, the fallout irradiates a lizard's nest. Decades later, an enormous sea creature suddenly attacks a Japanese fishing vessel in the South Pacific, leaving only one fisherman alive. Dr. Niko "Nick" Tatopoulos, an NRC biologist, is sent to Tahiti and to Jamaica, where a wrecked village, footprints, and ship are found. Nick collects skin samples that lead him to believe the creature is an enormous mutant created by nuclear testing. It travels to New York City during the rainiest week of the season, leaving a path of destruction in its wake.
Tourists Ben Hildebrand and Eric Kirby decide to parasail around the island of Isla Sorna. A creature of unknown species attacks and kills the boat crew as it passes through a fog bank, but Ben uncouples the line, and with Eric bound with him, he goes sailing into the wilderness.