While relaxing in the jungle, Horton the elephant hears a distinctive voice coming from what seems to be a tiny speck floating on the breeze. Horton manages to rescue the speck, and discovers that an entire tiny world, populated by the Whos, lives upon it. Unfortunately, he is the only one who can hear them.
Horton's unusual behavior catches the attention of jungle busy-body Kangaroo, who tells Horton that he is delusional. The only things that are real, she tells him, are those things that you can see, hear, and touch. She launches a campaign to destroy the speck, and have Horton caged. But no matter the threats, Horton remains faithful to his charge "one-hundred percent," and in the process helps the entire jungle to learn that "a person's a person, no matter how small."
Movie Sermon's General Warning
Horton Hears a Who! contains moments of peril that might be frightening to very young children.