Castle Skull

"The great magician, Maleger, has bought Schloss Schèadel (Castle Skull) on the Rhine and has transformed it into a fitting abode for his stage persona, replete with all the trappings of gothic romance. When a man is seen atop the battlements, running aflame and then plunging to his doom, the calamitous reputation of the Castle seems to have become reality. And when Maleger himself is found drowned in the great river, Inspector Bencolin is sent to investigate how the magician was killed, within an apparently sealed room, with only a small group of suspects on the ill-fated fortress at the time"--