You know what they say—the bigger the animal, the bigger its heart. And in Horton Hears a Who, we meet a kind-hearted elephant named Horton, who lives in the Jungle of Nool. Horton's a totally easygoing guy. He's open to all kinds of stuff, so when he hears a tiny voice calling out to him, he doesn't freak out.
Instead, he meets the Whos, a whole city of people that he can't exactly see, but he can certainly hear them. (Those big ears are coming in handy.) Just one problem. The other animals can't hear the Whos, so they think he's gone completely cuckoo. They mock him endlessly and threaten to snatch up his clover puff and destroy it. Not okay.
In the end, Horton stands up for the Whos, and the Whos make a huge ruckus to prove their existence to the rest of the gang.