Ernie does a "step-step-step-hop" dance as his clue before Big Bird is transported to a dancing land; where every creature, plant, and object moves exclusively in a rhythmic fashion (there's even a swaying sun). In order to find Ernie, Big Bird has to find someone who can copy Ernie's dance. He's sidetracked on his quest by a break-dancing hippo, a tap-dancing Two-Headed Monster, and some salsa-dancing hot peppers. Eventually, Big Bird comes across a large, sentient rock who correctly does Ernie's dance, and thus finds Ernie hiding behind him.
