No case is too strange or too baffling for the policeman George Felse and his son, Dominic. Over 13 instalments and two decades, the Felse Investigations will take them from their home on the Welsh Borders to the southernmost tip of India. Singers and musicians are gathered for a weekend course in folk music at the impressive neo-Gothic country mansion Follymead. Most come only to sing or to listen, but one or two have non-musical scores to settle. When brilliantly talented Liri Palmer sings 'Black, black, black is the colour of my true-love's heart!', she clearly has a message for someone in the audience. Passions run high, and there is murder brewing at Follymead. Among the music students are Dominic Felse and his girlfriend Theodosia. When not one, but two, members of the group go missing from the hall, Dominic calls upon his father, Detective Inspector George Felse, to help him solve this most perplexing mystery.