This title was previously published as The Boomerang Clue.

The accident -- Concerning fathers -- A railway journey -- The inquest -- Mr. and Mrs. Cayman -- End of a picnic -- An escape from death -- Riddle of a photograph -- Concerning Mr. Bassington-ffrench -- Preparations for an accident -- The accident happens -- In the enemy's camp -- Alan Carstairs -- Dr. Nicholson -- A discovery -- Bobby becomes a solicitor -- Mrs. Rivington talks -- The girl of the photograph -- A council of three -- Council of two -- Roger answers a question -- Another victim -- Moira disappears -- On the track of the Caymans -- Mr. Spragge talks -- Nocturnal adventure -- "My brother was murdered" -- At the eleventh hour -- Badger's story -- Escape -- Frankie asks a question -- Evans -- Sensation in the Orient Café -- Letter from South America -- News from the vicarage.

While playing an erratic round of golf, Bobby Jones slices his ball over the edge of a cliff. His ball is lost, but on the rocks below he finds the crumpled body of a dying man. The man opens his eyes and with his last breath says, "Why didn't they ask Evans?" Haunted by those words, Bobby and his vivacious companion, Frankie, set out to solve a mystery that will bring them into mortal danger.