A nearby meteorite crash blocks off the dinosaurs' water supply, starting an ecological chain-reaction that threatens life in the valley. All the dinosaurs, including a group of stupid bullies, must cooperate in an effort to free the blockage, which involves a risky venture outside the valley.

When a swarm of "leaf-gobblers" devours all the green food in the Great Valley, the herds move on to find another valley of greens and in the process, Littlefoot and his friends Spike, Cera, Petrie and Ducky wind up on an island in the middle of the Big Water. They're reunited with Chomper...Along with his nasty, hungry parents.

Segments: "A Rustic Ballad," a story of feuding hillbillys; "A Tone Poem," a mood piece set on a blue bayou; "A Jazz Interlude," a bobby-soxer goes jitterbugging with her date at the malt shop; "A Ballad in Blue," dark room, rain and somber landscapes illustrate the loss of a lover; "A Musical Recitation," the story of Casey at the Bat; "Ballade Ballet," ballet dancers perform in silhouette; "A Fairy Tale with Music," Peter and the Wolf; "After You've Gone," four musical instruments chase through a surreal landscape; "A Love Story," about the romance between a fedora and a bonnet; "Opera Pathetique," the story of Willie, the Whale Who Wanted to Sing at the Met.

Live-action segments show members of the Disney staff touring South America and recording their impressions in sketches. These segue into four animated sections: "Lake Titicaca" depicts tourist Donald Duck's troubles with a stubborn llama; "Pedro" tells of a little mail plane's adventures flying over the treacherous Andes; "El Gaucho Goofy" transplants an American cowboy into the Argentine pampas; and in "Aquarela do Brasil," Jose Carioca shows Donald the sights and sounds of Rio de Janiero.