In the film, the title group comprises Leo, Annie, Quincy, and June; all of them meet a little caterpillar. The caterpillar sings a song, Leo conducts to it, while the Little Einsteins sing it. They then discover a green truck with a tree on it. When the caterpillar gets in the back of the truck, he waves goodbye to the Little Einsteins but the truck hits a bump - ejecting the caterpillar. Annie tries calling out for the truck to stop, but it drives away leaving the caterpillar behind. From here, the caterpillar joins the team on their mission.