After being mysteriously summoned to the castle of Professor Orloff (or Doctor or whatever), a doctor is having a hard time getting the local townsfolk to give him a lift. I'm assuming it's because he keeps asking people to give him a ride to Professor Orloff's Castle and they've all seen some of the movies instead of asking for a lift to the Happy Funtime Cupcake Palace & Brewery Strip-Club Emporium and waving around coupons for 25% off. That's how I would do it.
Anyway, the carriage carrying the doctor to the castle gets stuck in the mud, and the doctor has to get out and push but he does a crappy job because he's wearing a cape and sporting the Dry Look.
The doctor hoofs it to the castle, and once he arrives all sorts of odd things start happening; and by "odd things" I mean "boring things" like wine bottles floating around. Seriously, drink enough wine and all sorts of stuff seems to start floating around. No big deal.
After an owl-based flashback, a woman steals jewels from Orloff's not-dead dead daughter. The thief decides to admire herself by a stream a la Narcissus even though the hounds are on her trail, and she gets caught and whipped until her blouse pops open which seems likely. Then there's an owl-based flash-forward and another woman gets chased around until her blouse pops open which again seems likely. There's an awkward and confusing hay-based love scene, and by "love" I mean "incredibly offensive rape by invisible ape-man", some other junk happens, and then the movie ends.
Dr. (or Professor) Orloff Vs. (or And or Against) The Invisible Man (or Monster) is boring and should be avoided unless you like looking at a castle in need or a good mopping or at the very least a wipe down with a few sprays of Windex and some paper towels.