The little mermaid Thalassa lives in a labyrinthine underwater temple deep in Lake Constance. One night, she discovers a mysterious piece of wood - which she believes to be a remnant of a real magic flute. Intrigued by its magic, she begins to build her own enchanted instrument. But what is so special about a magic flute? While Thalassa tinkers, she tells the children about brave princes, clever birds and music that can change entire worlds. A poetic and imaginative introduction to the world of opera.