Gerard and Isabelle live with their grandparents, not far from a forest. One day, Vincendon, a friend of their grandfather, tells them that he has been able to make an old maple sing which has died two years ago. The children are intrigued, more especially since the tree was cut down! Is he a wizard? After months of work in secrecy, the two children discover a surprise, the old man transformed the maple into a violin.