Harold wants to take a walk in the moonlight, so he draws a moon with his purple crayon. Next Harold wants a picture for his room, soon he's bigger than a mountain. Then with his crayon, Harold takes a trip through the enchanted garden where he meets

Although they are many different colors, the crayons in a box discover that when they get together they can appreciate each other and make a complete picture.

One day, Duncan is happily coloring with his crayons when a stack of postcards arrives in the mail from his former crayons, each of which has run away or been left behind, and all of which want to come home.