A radio detective sets out to solve an old murder case, with the help of her sound man and another radio detective. They manage to talk to the people involved in the case, but shortly afterwards the main suspects turn up dead.
Dr. Hohner, theatre physician at the Vienna Royal Theatre, murders his mistress, the star soprano when his jealousy drives him to the point of mad obsession. Ten years later, another young singer reminds Hohner of the late diva and his old mania kicks in. Hohner wants to prevent her from singing for anyone but him, even if it means silencing her forever.