To begin the story, the Cat encourages the Boy to think up the Jungle of Nool, where Horton the Elephant is bathing. Horton hears a strange noise coming from a nearby speck of dust, and reasons that someone must be on it, calling out for help. He carefully places the speck on a soft clover and decides to guard it ("Horton Hears a Who"). But he is mocked mercilessly by the Sour Kangaroo and the other animals of the jungle, who do not believe him ("Biggest Blame Fool"). The only exceptions are Horton's bird neighbors, Gertrude McFuzz, who admires his compassion, and Mayzie LaBird, who is more concerned about herself.