Bobby Jones is retrieving a wayward golf ball at the base of a cliff when he discovers an unconscious man whose back is broken. The man regains consciousness long enough to utter the words "Why didn't they ask Evans?" before he dies. A few days after the inquest, Bobby is drugged when someone slips what should have been a deadly dose of morphine into his beer. Bobby decides to investigate the matter further and his friend Lady Frances Derwent agrees to help. The two of them are soon hard at work to discover the murderer of the dead man, but as they approach the truth, they find their own lives in danger.