It's 1934 in Transylvania Heights and villagers are celebrating the death of mad scientist Dr. Victor von Frankenstein. Forced to deal with the issue of his grandfather's property, reluctant heir Frederick Frankenstein (that's Fronkensteen) makes his way to Transylvania, where he meets hunchback Igor (that's Eye-gor), curvaceous lab assistant Inga, and housekeeper Frau Blucher. Upon a very startling dream, Frederick and Inga discover the late Frankenstein's secret laboratory, including notes covering all of his experiments reanimating the dead. Frederick decides to continue this work and collects a corpse from the cemetery. He sends Igor to procure a suitable brain, which Igor drops and replaces with one he claims was labeled "Abby Normal." Just as the creature comes to life, he storms out of the castle (with a little help from Frau Blucher) and sets out to ravage the town.
While everyone is out looking for the monster, Frederick's fiancée Elizabeth shows up unexpectedly at the castle and finds Frederick and Igna in a rather compromising situation. Meanwhile, the monster has befriended Harold, a blind hermit, who, despite taking him in and feeding him, accidentally sends the monster into another fit of rage when he pours hot soup in his lap and mistakes his finger for a cigar. Frederick finally corners the monster and calms him down. To quell the townspeople's fears, Frederick arranges to present the monster at the Loews Transylvania Theatre where he delights the audience with Irving Berlin's "Puttin' on the Ritz." At the end of his number, the monster is startled when the stage lights explode. He kidnaps Elizabeth and takes her to a cave where she sees - ahem - a different side of the monster. Despite his attempts to lure the monster home, Frederick fails to perform an intelligence transfer and he is forced to publicly accept his family name before being hanged by Inspector Kemp and the angry villagers.
The monster awakens to find the transfer was indeed successful and he now has Frederick's brilliant mind. With this he is able to determine that Frederick is not dead, just unconscious, and brings him back to life. A near hanging, two marriage proposals, and a "blind date" make for a happy ending for all. "Woof!"