As the storm begins to gather force, the electric cars stall outside of the tyrannosaur paddock. Looking around with a pair of night vision goggles, Tim spots the tyrannosaur clutching the fence with its forearms and realizes that the electricity has been cut off. Regis runs from the car, abandoning the children. The tyrannosaur attacks the car, picking it up and throwing it. Malcolm runs from the other car, but is caught by the dinosaur. Grant gets out of the car and the dinosaur spots him, but he realizes that the animal cannot see him if he remains completely still. The t-rex knocks the car over in frustration, which tosses Grant into the air.
Harding, Sattler, and Gennaro are forced to take a longer route back to the resort building because a tree has fallen in their path.
Nedry gets lost in the storm on his way to the dock and is killed by a venom-spitting dilophosaur.
Hammond and Wu sit in Hammond's bungalow and have dinner and ginger ice cream. Hammond laments that he may never see the day the children of the world enjoy his park. When Wu suggests that recent events indicate Hammond might have to change his park, Hammond launches into a tirade that no one can stop him from making as much money as he wants from his island. Meanwhile, security cannot find Nedry. Dr. Harding and company follow a group of compys that are off to scavenge a recently killed animal...
Tim narrowly escapes from the tree his Land Rover has landed in and finds Lex hiding in a drainpipe. Back in the lab, Wu realizes that frog DNA was used in all of the species that are reproducing.
Grant finds Tim and Lex. Regis emerges from hiding, but the other, more juvenile t-rex appears from the foliage and eats him. The others run for their lives.
Arnold reestablishes radio contact with Harding and company, instructing them to come back immediately. Hammond, finally informed of the technical problems and the fact that the group has not returned, is furious.
Muldoon and Gennaro take Harding's jeep out to find the tour group. They find Regis's leg near the t-rex paddock and wrap it up in a tarp. Exploring the area, Muldoon determines that some of the tour group are still alive. They find Malcolm, who is seriously injured, and bring him back.
Wu helps Arnold deconstruct the computer program Nedry used to disable the security and power system. Muldoon informs Sattler that she and Harding are going to have to take care of Malcolm. The phone lines are still down, so there is no way to get in touch with a doctor on the mainland.
Trying to get out of the tyrannosaur paddock, Grant and the kids scale a fence and cross a moat, finally taking shelter in a concrete shed that is filled with hay and equipment. They huddle together and sleep on the hay.
Arnold fixes the code and restores power to the park. The computers begin searching for Grant and the kids, but are unable to find them. Malcolm jokes with Harding and appears to be doing better, but Sattler tells Gennaro that he desperately needs to be taken off the island for surgery on his leg.
Muldoon heads out to fix a damaged portion of the electric fence. Arnold explains to Gennaro that he thinks Malcolm's interpretation of chaos theory does not apply to the park. Muldoon discovers that the t-rex has broken into the sauropod paddock. Hammond is livid at the prospect of losing a sauropod and instructs Muldoon to retrieve the t-rex that night. Muldoon refuses, claiming it is Hammond's fault that they lack the necessary equipment to bring down the tyrannosaurus.
Grant wakes up to find Lex feeding a baby triceratops. Arnold briefly shuts down the system to try to get the phone lines back up. Grant and the kids leave the shed and are caught in a stampede of hadrosaurs who are running away from a tyrannosaur. The three seek shelter on a small rocky outcropping and then climb a tree.
Grant and the kids go to a dock shed where they find a raft and a tranquilizer gun. On their way out they realize that the tyrannosaurus is sleeping right next to them. They inflate the raft and paddle out into the lagoon. Lex sneezes, awakening the t-rex. It follows them into the water, swimming after them like a giant crocodile. Just as it seems ready to snatch them up, however, it is distracted by the juvenile t-rex, which is trying to steal the sauropod carcass the larger t-rex had left ashore.
The first character to die by the jaws of a dinosaur is Nedry, who, as the novel's primary villain or henchman to this point, makes us feel a sense of retribution rather than shock at his death. The first major dinosaur attack occurs when the tyrannosaurus attacks the Land Rover in which the children are riding. Crichton makes the children the target out of this first attack to heighten the tension and suspense by playing on our sympathies. He takes this suspense a step further by narrating much of this section from the perspective of Tim, compelling us to imagine what it is like for an eleven-year-old to be assaulted by a full-grown tyrannosaurus rex.
While Tim is a good narrator—exceptionally intelligent and quick-thinking, interested in dinosaurs, and very mature for his age—Lex is somewhat younger and far less mature. She grows bored of the tour quickly, constantly asking if anyone will play catch with her. Regis usually complies, taking on a sort of temporary father role for her. When Regis flees the Land Rover, leaving the kids to fend off the t-rex themselves, Lex is quite scarred by the abandonment. Later, as Grant takes on the role of surrogate parent to Tim and Lex and the three escape into the park, Lex begs him Grant to leave them alone even for a minute. This request foreshadows several upcoming occasions in which Grant has no choice but to leave the kids alone for a brief time.
The fact that the first big dinosaur attack happens to Tim and Lex is, however, more than simple coincidence or plot device. In light of the idea of the hupia—the mythical ghosts that kidnap children—from the first section of the novel, we see a deeper significance. The dying guard's talk about hupia earlier in the novel links the hupia to the word "raptor" and the local lizard attacks. Now the connection between hupia and the dinosaurs of Jurassic Park is obvious: the dinosaurs seem to instinctively attack children. Although the idea is never brought up in the text directly and no possible explanation is ever offered, this is a technique Chrichton uses to vilify the dinosaurs. Since the novel's major conflict is the threat of these dinosaurs attacking people, the dinosaurs appear especially vicious when they target defenseless children.
The connection between the hupia and the velociraptors is particularly important. When the park visitors are in the nursery, the baby raptor is drawn to Tim. Later in the novel, when the raptors get loose, several of them go after Tim and Lex. As evidence grows that raptors have escaped to the mainland, the prospect of a whole population of these intelligent, baby-hungry beasts living in the jungles of Costa Rica appears especially frightening.