"The mad Count De Sade lives in his families' castle located on a remote island. Count De Sade keeps his wife locked up in a dungeon below the castle and his insanity strike fear in to the staff. After a terrible storm, a ship's captain and the son of the ship's owner find themselves washed ashore on this lonely isle, not knowing the danger they face from the evil Count De Sade."
Reading the description was more rewarding than actually watching The Dungeon Of Harrow. If you do choose to watch this movie then first stop at the store for plenty of hard liquor. Also, good news, this guy sums up the movie pretty well and he's far more entertaining than the entire film!
Now, that all said - if yous still want to watch the film you can, free, through the Internet Archive!