A team of scientists find a deadly strange animal/plant hybrid growing in the valley. Burt, Tyler and Cletus work with them to figure out how to stop it before it spreads even further. Meanwhile, Perfection has to deal with an over-excited tourist named Larry.

Larry returns to Perfection and wants to learn more about Cletus Poffenberger. Tyler tells him the story of when the Perfection residents first met Cletus and had to face his increasingly dangerous pet, Four-Twelve.

Residents of Perfection are facing money troubles and Rosalita decides to take a job at Melvin's latest business venture, the Oasis. But some of the water Melvin uses for the Oasis' lagoon actually came from Perfection and contains Mixmaster, creating a deadly six foot shrimp. And when Melvin's attempt to kill it drives the shrimp out of the lagoon, Tyler and the others will have to stop it before it escapes into the wild.