In the 13th century, in a stone castle on an island in the middle of a lake, princess Claire was modeling for her childhood friend Milo's painting. One day, Claire became bored and angry, and entered the Lost Forest on the outskirts of the castle town, where she was suddenly sucked into a space-time like a black hole. In the present day, Nobita and his friends were trying to use a secret gadget called the "Art Access Light" to enter the world of the painting and get references for the painting. When Nobita gave up on drawing the painting assignment and threw his eraser at the ceiling, a hole appeared in the ceiling, the eraser disappeared, and a painting fell instead. The painting had a bat that changed color like a hologram, and Doraemon and Nobita, who were curious about it, used the "Art Access Light" to enter the world of the painting in order to meet the girl in the painting.