In the jungle of Nool, the elephant Horton hears a voice in a speck; he uses a clover to rescue the speck of dust and he makes contact with the Mayor of Whoville. Horton discovers that in that tiny speck there is a city crowded with creatures and he decides to leave Whoville in a safe place. However, the evil Kangaroo does not believe Horton's story and thinks he's dangerous for the children of Nool, making them believe in what they can not see, hear or feel, and incites the animals against Horton.