In "Horton Hears a Who!", a kind elephant named Horton discovers a tiny world called Whoville on a speck of dust. He learns that the inhabitants, the Whos, are in danger and need his help. Despite being ridiculed by other animals, Horton believes that "a person's a person, no matter how small," and vows to protect the Whos. As Horton faces challenges and skepticism, he remains determined to save his tiny friends. The story teaches important lessons about kindness, friendship, and the importance of every individual, no matter their size. In the end, the Whos unite to make their voices heard, proving that everyone matters.