Start with the premise that you will do anything to replace your lost love with a look-alike. Throw in your scientific knowledge of a deforming disease (isn't this the stuff that Leo G. Carroll contracted from the spider venom in "Tarantula"). Throw in the fact that the main character, instead of finding some way to attract the young woman, engages in heavy-handed stalking, until he totally draws attention to himself and has to hatch this insane plot: If he can make the girl's father sick, then help him recover, she will marry him. The problem is that most of the events are random and unpredictable. Anyone with half a brain would have seen through things. There's a third party, a woman that the doctor, played by J. Carroll Naish, has treated with great insensitivity. You know she is going to be a factor. There's also a gorilla kept in a cage who is used occasionally for heaven know's what. Oh well. There is so little sense to this who thing that it plays itself out and people get their just desserts.