Eleven-year-old twins, Demi and Semmy are haunted by a different yet familiar sound. They thought they knew all the sounds as music is a big part of their lives. So who or what is making this disturbing sound? Can their great-grandmother help solve the mystery? Or do they have to be brave and find this strange musician on their own? If the twins are brave, what will happen to them if they befriend this stranger? Could it change their lives forever? There is only one way to find out!