After stopping a major T-rex fight at Prehistoric Park, Nigel goes back 300 million years to prehistoric Scotland in search of some giant creepy crawlies. He soon encounters a swarm of dragonflies the size of eagles and a 10-foot millipede but fails to catch them.

Back at the park, vet Suzanne tries to save the life of the injured T-rex while head keeper Bob tries giving the Titanosaurs rocks to eat to improve their behavior. Later, Suzanne tries to get the two saber-toothed cats to have cubs by improving their special breeding enclosure.

That night, back in prehistoric Scotland, a giant scorpion visits Nigel's camp but once again slips through his fingers leaving him empty handed. Next day, after changing his strategy, he manages to bag a giant dragonfly and a scorpion in quick succession. But the scorpion stings Nigel as he releases it into a container and then a forest fire threatens to cut them off from their jeep. On the way to the jeep, Nigel and his team manage to catch a giant millipede before getting one of the Titanosaurs to tow the disabled jeep through the portal back to the park.

Back at the park, the scorpion sting turns out to be harmless, the injured T-rex recovers and the two saber-tooths look like they may be ready to breed.