When a young Chinese-Austrian boy invites his best friend Danny to spend the summer at his grandfather's house on Hainan Island in China, the two friends must work together to save their elderly host's shadow theater from loan sharks. Little does Danny realize that a marionette named Mozart has come to life, and hitched a ride to China in his suitcase. As the old man and his granddaughter Lin Lin work to restore the theater, Danny and the girl form a fledgling friendship and Mozart falls in love with the beautiful shadow princess. Meanwhile, as Mozart composes the "Chinese Sonata" for his true love, the theater is threatened by circling loan sharks. Upon witnessing Mozart and his friends come to life in the shadow theater, the kids and the puppets collaborate on a plan to save the theater once and for all.