Joe Sixsmith is going west. But only as far as Wales where they keep a welcome in the hillside and the Boyling Corner Choir has been invited to take part in the Llanffugiol Choral Festival. Trouble is, no one seems to have heard of Llanffugiol, and all they find on the hillside is a burning house with a mysterious woman trapped inside.
Soon Joe is surrounded by a whole bevy of suspicious characters, not to mention the kind of criminous confusion that turns into utter chaos when confronted with the famous Sixsmith detection technique. Joe is no quitter, though. Doggedly, aided by little more than that instinct for truth which is his unique talent, he moves forward over the space of an single weekend to uncover crimes which have lain buried for years.