While all his classmates bring amazing circus animals to show and tell, Patrick's only contribution is a small, shy hermit crab. As Patrick stands awkwardly silent in front of his class, he begins to feel nervous in his stomach. Seeing his discomfort, Miss Hansen sends him to the school nurse who shows Patrick an x-ray revealing a group of butterflies in his stomach. Patrick tries to figure out how to make the butterflies leave, to the confusion of his parents who find Patrick sticking his face onto the end of a leaf-vac. Later, at an amusement park with his mother, Patrick must confront the butterflies as he finds himself terrified on a rickety old roller coaster, all the while knowing that show and tell is coming again tomorrow