The summer music school at Falconbury proves to be more eventful than any of the students or the lecturers could have imagined. The school is in the country, but many of the pupils and their instructors have travelled from the Royal School of Music in London. Derek Fox and his fiancee Belinda Power fail to turn up on time and nobody knows where they are.

When the body of Belinda is discovered inside one of her own timpani, suspicion falls on Derek, who turns to Dr David Wintringham for help. But Derek is not forthcoming with information leaving David with little to go on. What is Derek hiding? And who killed Belinda if Derek is innocent?