Four years after Jurassic Park's genetically bred dinosaurs ran amok, multimillionaire John Hammond shocks chaos theorist Ian Malcolm by revealing that Hammond has been breeding more beasties at a secret location. Malcolm, his paleontologist ladylove and a wildlife videographer join an expedition to document the lethal lizards' natural behavior in this action-packed thriller.

On July 2, a giant alien mothership enters orbit around Earth and deploys several dozen saucer-shaped "destroyer" spacecraft that quickly lay waste to major cities around the planet. On July 3, the United States conducts a coordinated counterattack that fails. On July 4 the a plan is devised to gain access to the interior of the alien mothership in space in order to plant a nuclear missile.

A wealthy entrepreneur secretly creates a theme park featuring living dinosaurs drawn from prehistoric DNA. Before opening day, he invites a team of experts and his two eager grandchildren to experience the park and help calm anxious investors. However, the park is anything but amusing as the security systems go off-line and the dinosaurs escape.