In BARBIE AND THE SECRET DOOR, Princess Alexa, a thoughtful, book-loving princess (played, of course, by "Barbie," voiced charmingly by Kelly Sheridan and sung well by Brittany McDonald), lives in a beautiful castle with her very caring family. The problem is, the princess is shy and unsure of herself, and she shrinks from some of her princess duties such as meeting new people, making speeches, and attending castle balls. She's content to stay in her room surrounded by her books, hiding from all but her family and her supportive ladies-in-waiting. When she finds a secret door, opens it, and enters a magical kingdom, her life changes forever. Fairies, mermaids, unicorns, and adorably unique little creatures live there, and they're desperately in need of Princess Alexa's help. They're fighting to protect their way of life from a formidable villain in the person of Malucia, a naughty, mean-spirited little girl with ponytails, a sneering smile, and a desire to possess all the magic in her kingdom. Princess Alexa must find the courage to do battle with Malucia, learn to value herself and her talents, and open her heart to new experiences and new people.