The story begins with Beavis and Butthead passing by a ceremony announcing the grand opening of "Jurassic Park". They decide to attend, hoping to see some dinosaurs. John Hammond declares the park open, and visitors flock the helipad, with the big headed duo joining the crowd. Upon arrival at the park, the duo embarks on their journey to see all the dinosaurs. During their time, they mock a few of the dinosaurs and make remarks on how cool others are. However, at the Dilophosaurus exhibit, they fall in. When a Dilophosaur appears, they find it cool at first, but begin to hold a grudge against it after it eats their nachos. They declare war on the creature and gather all sorts of tools to kill it. When they encounter it again, it almost strikes Beavis down, but the duo regain the upperhand, and Butthead beats the creature to death, drawing the attention of the other Dilophosaurs, who chase the duo away, then mourn the loss of their comrade. The duo climb back out of the enclosure and continue their journey. At one point, they arrive at the Giganotosaurus enclosure and taunt the creature into breaking out. The creature chases them through the park until they reach the T-Rex enclosure, and taunt the Tyrannosaurus into breaking out. The two dinosaurs battle, with the T-Rex coming out on top, and roaring in victory before being sedated by rangers and put back in it's enclosure. The boys continue their adventure, arrive at the Velociraptor enclosure, and tease the raptors before one tries to bite Beavis. After the day is over, the duo leave and return to the mainland. Back on the island, all the creatures have escaped, as a result of the Giganotosaurus accidentally deactivating the security during it's rampage.