 In 1858 France, Emperor Louis Napoleon (David Bond) sends Captain Renault (George Montgomery) of the Royal Dragoons, Minister La Roche (Berry Kroeger) and Major Nicolet (William Conrad) to Normandy in search of the members of a group of rebels. A Masked Cavalier (Paula Corday), the niece, Lady Christianne, of the Marquis De Montableau (Robert Warwick), announces at a secret meeting of the Normandy underground leaders that the fabled treasure of Monte Cristo was willed to her and she will use it to finance their cause. Her uncle, the only one who can decipher the symbols on the sword of Monte Cristo, the key to the treasure, derides her stand against the Emperor. La Roche takes possession of the sword and has the Marquis put into the dungeon. Christianne, as the Masked Cavalier, regains the sword from La Roche, but Captain Renault apprehends her and returns to sword to La Roche.