When Cowman is assigned the task of guarding the Jurassic Corn Kernel at the county fair, Professor Mertin Fargleman (Tom Kenny) wants to steal it to win the Gardening Award posing as Professor Twineyvines. When the town is impressed with Twineyvines and unimpressed with Cowman trying to save the Kernel from him, Twineyvines becomes the new protector. Immediately, Cowman takes the kernel to protect it and is branded a thief and then chased by a mob. He then decides to stop Twineyvines when Cowgirl finds Cowman and Ratboy headed for Peru and says that Green Rooster, Mr. Hamtastic and Paranoid Man have been kidnapped by Mrs. Beady, who they do not know is in line with Twineyvines. Now, Cowman, Ratboy, Cowgirl, Mr. Hamtastic, Paranoid Man and Green Rooster must unite to defeat Fargleman, clear Cowman's name, and save the Jurassic Corn Kernel (mutated into a giant monster) from destroying the fair (even though the fair was already destroyed).