Harold has the power to create a world of his own just by drawing it with his purple crayon.

Harold 's a inquisitive 4 year old, and with his purple crayon, he has the power to create a world of his own - just by drawing it. Harold wants to go for a walk in the moonlight, but there's no moon, so he draws one. He has nowhere to walk, so he draws a path. Harold has many adventures as he goes in search of his room.