"I have been in the Valley of Fear... I am not out of it yet." "There - is - danger!" The warning message decrypted by Sherlock Holmes arrives too late to save John Douglas of Birlstone Manor, Sussex, an American gentleman gruesomely murdered in his study by person or persons unknown. But who was John Douglas, why wasn't he wearing his wedding-ring, and what is the crucial significance of the missing dumb-bell?