John Hammond’s grandson, Tim is dropped off on Isla Nublar with his older sister, Alexis (or “Lex”) for the weekend so that they can escape their parent’s divorce. Tim shows a fascination with Dr Alan Grant and his work, although Alan seems less enthusiastic about Tim. Tim discovers gastrolithes near the sick Triceratops that the visitors witness, which helps Dr Ellie Sattler solve the problem of why it is ill.
Later, when the tour vehicles are forced to stop outside the Tyrannosaurus paddock, Tim looks inside the paddock through night-vision goggles, to see that the goat placed within the paddock to feed the dinosaur is missing; the goat then lands on the vehicle roof. The Tyrannosaurus breaks out of its paddock, and Donald Gennaro leaves Tim and Lex in their tour vehicle, running away to hide. The children create enough ruckus for the dinosaur to notice them, and it attacks their vehicle; while Alan saves Lex, Tim remains stuck in the vehicle as the Rex pushes it (along with Alan and Lex) over the edge of its paddock.
Alan helps Tim out of the car; he states that he threw up. The three sleep in a tree for the night, and continue trekking through the paddock the next day. When they pass over the paddock fence, Ellie happens to reactivate it; as Tim is still on the fence, he is electrocuted and sent flying to the ground with stuck-up hair.
The group reaches the Visitor’s Center; Alan leaves the kids in the restaurant, where they eat until noticing a Velociraptor shadow. They hide in the kitchen, but are attacked by two Raptors; Tim locks one in a walk-in freezer. The two then escape the other Raptor, meet Alan and Ellie and hide in the maintenance room. After Lex re-boots the systems, the group must escape from the room before a Raptor breaks in; they clamber through the ventilation system until collapsing into the main hall. As the Raptors prepare to kill the four, the Tyrannosaurus appears and a fight breaks out between the carnivores. Tim is able to escape the island.