A dark shadow looms over the Rhineland where Inspector Henri Bencolin and his accomplice Jeff Marle have arrived from Paris.Entreated by the Belgian financier D'Aunay to investigate the gruesome theatrical death of actor Myron Alison, the pair find themselves at the imposing hilltop fortress Schloss Schadel, in which a small group of suspects are still assembled... A sequel to 'It Walks By night', featuring Inspector Henri Bencolin.