A mischievous ghost named Mr. Majeika possesses his new teacher, Mr. Potz, and turns the classroom upside down. Mr. Majeika, a ghost with a penchant for pranks, finds himself in a new school and a new body. His objective is to cause as much chaos and fun as possible, much to the dismay of the students and the bewildered Mr. Potz. The primary forces opposing him are the school's strict headmistress, Mrs. Cragg, and the general orderliness of the school day. The narrative unfolds from the perspective of the students, observing the bizarre transformations of their teacher.

The Mr. Majeika series is generally well-regarded for its lighthearted humor and imaginative premise, appealing to young readers who enjoy whimsical stories. This particular installment, focusing on the music teacher, likely continues the tradition of playful disruption and comedic misunderstandings. The narrative structure, often told from a child's perspective, allows for relatable observations of adult eccentricities. The book's reception is typically characterized by its ability to entertain and engage children with its unique blend of the supernatural and the mundane.