Classic drama based on the stage play by Edgar Wallace. The story revolves around the aristocratic Lebanon family, with Dowager Lady Lebanon (Helen Hayes) harbouring a dark secret. It seems that every generation or so, the Lebanon clan produces a homicidal maniac. The unfortunate candidate this time around seems to be Lord Willis Lebanon (Marius Goring), a fact that the Dowager Lady hopes to hide from the world. Alas, blood will tell and murder will out.