On her way to see her parents, she passes through various places: The Land of Yellow and Blue, The Land of Red and Yellow, and The Land of Red and Blue. At each place, she finds that although the people all look different, they still live in peace because they respect each other. When she reaches The Land of Black and White where her parents live, she finally comes to understand that she belongs in her color-filled world just as much as everyone else.

The gray caterpillar then becomes a beautiful rainbow-colored butterfly, destined to spread the word about self-acceptance, empowerment, belonging, and love: "Are you green, orange, purple, or gray? Don't be sad; you're okay."

Entertaining while also teaching, Hues and Harmony uses lyrical text and beautiful images to re-imagine the world and its different peoples as it simultaneously highlights commonalities in a fun and relatable way. It is a must read for anyone who has ever felt like they don't belong, for those who want to help them, and for those who don't understand how "outsiders" feel.