Horton Hears a Who!.A dust speck is dislodged from its obscure place and sent adrift through the Jungle of Nool. At the same time, Horton the elephant (Jim Carrey), the jungle's eccentric nature teacher, takes a dip in the pool. The dust speck floats past him in the air, and he hears a tiny yelp coming from it. Believing that an entire society of microscopic creatures are living on that speck, he places it atop of a clover. Horton finds out the speck harbors the city of Whoville and its inhabitants, the Whos, led by Mayor Ned McDodd (Steve Carell). He has a wife, Sally (Amy Poehler), 96 daughters (whose names all begin with the letter H), and one teenage son named JoJo (Jesse McCartney). Despite being the oldest and next in line for the mayoral position, JoJo doesn't want to be the next mayor, and because he's so scared of disappointing his father, never speaks. Once Horton begins carrying the speck with him, the city starts experiencing strange phenomena (earthquakes and 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 (Dan Fogler). After he makes contact with Horton, the Mayor finds out from Dr. Mary Lou LaRue (Isla Fisher) that Whoville will be destroyed if Horton does not find a "safer, more stable home". Horton resolves (with the help of his best friend Morton the mouse (Seth Rogen) to place the speck atop Mt. Nool, the safest place in the jungle. The head of the jungle, the Sour Kangaroo (Carol Burnett), disbelieving Horton's beliefs and resenting him for overshadowing her authority, attempts several times to demand that Horton give up the speck, but Horton ignores her demands. Also taking force toward Horton are the Wickersham Brothers, a group of monkeys who love making misery. Eventually, the Kangaroo enlists a vulture named Vlad Vladikoff (Will Arnett) to get rid of the speck by force...