In the grounds of a dark, deserted mansion, a blackmailer collects money from his victim. Meanwhile, Peter (John Horsley, THE FALL AND RISE OF REGINALD PERRIN), chemist and philanderer, realises that the drinks of himself and his mistress, Madeline, have been poisoned. He phones Dr. Cole but Madeline dies. But when Mrs. Cole is brutally murdered and Peter is the chief suspect, Peter's snubbed fiancée takes up the case.