The adventure begins when Princess Diana is told by the king and queen that there is to be a big ball in the castle. Princess Diana believes she is the most beautiful girl in the whole world, but when she gets to the ball, she discovers she is not the most beautiful girl there and becomes jealous. Princess Diana sets out to become the most beautiful girl in the whole world. She first encounters the ugly old lady Elder, who is patient and wise. She sends Princess Diana to the castle in search of the Magic Light Beam. Princess Diana is turned into an ant by the Magic Light Beam. Now Princess Diana must find a way to turn back into a human princess again. She seeks the advice of a spider named Spidy, a ladybug, a caterpillar named Callie, and finally, the truly beautiful Purple Butterfly. Along the way, Princess Diana learns about vanity and the meaning of true beauty.