A lonely girl draws a magic door on her bedroom wall and through it escapes into a world where wonder, adventure, and danger abound. Red marker in hand, she creates a boat, a balloon, and a flying carpet that carry her on a spectacular journey toward an uncertain destiny. When she is captured by a sinister emperor, only an act of tremendous courage and kindness can set her free. Can it also lead her home and to her heart's desire?

A king emerges from a hidden door in a city park, startling two children sheltering from the rain. Just as he pushes a map and some strange objects into their hands, he is captured by hostile forces that whisk him back through the enchanted door. Colored markers in hand, they go on a quest through the portal, under the sea, across a tropical paradise, over a perilous bridge, and high in the air with the help of a winged friend and their imaginations to rescue the king and his kingdom from darkness.

Failing to get the attention of her busy father, a lonely girl turns back to a fantastic world for friendship and adventure. It's her third journey into the enticing realm of kings and emperors, castles and canals, exotic creatures and enchanting landscapes. This time, it will take something truly powerful to persuade her to return home.