As Frederick promised in "Finale Ultimo", the sequel was coming soon. Well, consider this that sequel.
Eighteen years have passed since the events of Young Frankenstein. Elizabeth and the Monster have been living happily ever after (having tons and tons of crazy sex). Frederick and Inga have had not only the son of frankenstein, but the daughter as well. And the village has been peaceful (except for the occasional monster crashing through).
But now something new threatens the village. A horrible creature that is hunting down the villagers one by one and ripping them apart. A creature that seems to only come out during the full moon.
Of course, everyone suspects a werewolf. And everyone suspects the residents of Frankenstein castle.
So now it is up to the the Frankenstein family and their friends to clear their name and find the real culprit.