Plot[edit]
In the Jungle of Nool, Horton the Elephant, the jungle’s eccentric teacher, hears a tiny yelp coming from a floating dust speck and gives chase to it before placing it on top of a pink flower. Horton finds out the speck harbors the city of Whovilleand its inhabitants, the Whos, led by Mayor Ned McDodd, whose family includes his wife Sally, 96 daughters whose names all begin with the letter H, and one young son named JoJo. Despite being the oldest child and next in line for the mayoral position, JoJo does not want to be the next mayor, and he does not talk because he is so scared of disappointing his father. Once Horton begins carrying the speck with him, the city starts experiencing strange phenomena (earthquakesand changes in the weather), and the Mayor finds his attempts to caution Whoville challenged by the Town Council, led by the opportunistic yet condescending Chairman.
After he makes contact with Horton, the Mayor finds out from local scientist Dr. Mary Lou LaRue that Whoville will be destroyed if Horton does not find a "safer, more stable home". With the help of his best friend Morton the mouse, Horton decides to place the speck atop Mt. Nool, the safest place in the jungle. The head of the jungle, the Sour Kangaroo, who refuses to believe that the Whos exist, demands numerous times that Horton give up the speck for overshadowing her authority, but Horton refuses. Also taking force toward Horton are the Wickersham Brothers, a group of monkeys who like to cause havoc around the jungle. Eventually, the Kangaroo enlists a sinister but idiotic vulture named Vlad Vladikoff to get rid of the speck by force. He initially only agrees to do it in exchange for the Kangaroo's son Rudy, but when she threatens to hire the Wickersham Brothers to do it as she will probably change her mind, he eventually decides to do it for free.
Vlad does many attempts to steal the flower, but Horton outruns him. In a last attempt to steal it, Vlad manages to steal the flower away from Horton and drops it into a massive field of identical pink flowers causing a large tremor in Whoville. After unsuccessfully picking 2,999,999 flowers, Horton eventually recovers the flower (exactly the 3,000,000th flower), also revealing himself to the rest of Whoville. The Kangaroo eventually finds out that Horton still has the speck, fires Vlad, and rallies the jungle community into arresting Horton, preying on their fears that their own children will become chaotic delinquents under his influence.
Upon cornering him, the Kangaroo offers Horton a final chance to renounce Whoville's existence. Horton refuses, and despite the heartfelt speech that he gives, the Kangaroo orders the animals to rope and cages him, and to have the speck and Whoville destroyed by dropping it in a pot of beezlenut oil. The Mayor enlists all of his people to make noise so that all the animals will find out they're really there, assisted by JoJo's "Symphonophone", an invention that creates a huge musical contribution and reveals that JoJo's "true" passion is music but still fails to penetrate the surface of the speck.
The Kangaroo snatches the flower from the captured Horton and prepares to drop it into the pot. Meanwhile, JoJo grabs the horn that was used to project Horton's voice, runs up the highest tower, and screams his first word which is "No", breaking through the sound barrier just seconds before the speck hits the oil. Rudy grabs the flower and proclaims he hears it, and the other animals of Nool notice that they hear it too. Despite his mother's objections, Rudy returns the flower to the released Horton, while the animals, realizing the truth about the Whos' existence, turn on the Kangaroo for deceiving them. While being praised for his integrity by his neighbors, Horton forgives the devastated and regretful Kangaroo, who befriends him with a makeshift umbrella for Whoville. The film ends with the Whos and the animals of Nool gathering to recite the chorus from "Can't Fight This Feeling" by REO Speedwagon, and it is revealed that the Jungle of Nool (and Earthas a whole) is just one speck, like Whoville, among numerous others, floating in space.
