Synopsis: Each night, when Den falls asleep, his Crayons enter a magical Crayon Box that transports them to Color City, a world of dazzling hues and soaring fantasy. When timid Yellow is accidentally left behind in Ben's room, she inadvertently awakens two Unfinished Drawings. They follow Yellow o Color City where they wreak havoc and stop the flow of the enchanted Rainbow Waterfall that provides all the color to the Crayons. It's up to Yellow and her fellow Crayon pals to save the day and bring back the color!