Noble-born cad Denis (Stapley) has been tricked into a forced stay at the eerie manor of the Sire de Maletroit (Laughton), an evil madman who can't get over the death of his beloved, 20 years after she married his brother (Cavanagh) instead, then passed away during childbirth. Maletroit is determined to have his revenge: the brother has been stowed away in the dungeon...