Bobby Jones, the son of the vicar of the Welsh seaside town of Marchbolt, discovers a badly injured man who has apparently fallen off the cliff. The man soon dies, but not before briefly regaining consciousness and saying “Why didn’t they ask Evans?”.
As a string of fishy incidents unfurls, Bobby becomes convinced that the man’s death was no mere accident. Reunited with his childhood friends, Lady Frankie Derwent and Knocker, they decide to play the part of amateur sleuths and uncover the truth.