Tenebras -- a phantom-like criminal who defies all the police of Europe. Against him are arrayed the forces of Harry Dickson, the American Sherlock Holmes, and the dynamic Inspector Loustaud of the French S ret , but also the Simpson Brothers, two ruthless American billionaires who will do anything in their power, and commit any crime, to seize the $1.5 million inheritance of young Teddy, the son of the beautiful Comtesse Dianah de Villerville.