It has been years since the events of the last movie. Baron Wolf von Frankenstein, son of Henry Frankenstein (creator of the Monster), relocates his wife Elsa) and young son Peter to the family castle in the eponymous village.
Wolf wants to redeem his father's reputation, but finds that such a feat will be harder than he thought after he encounters hostility from the villagers. Aside from his family, Wolf's only friend is the local policeman Inspector Krogh who bears an artificial arm, his real arm having been "ripped out by the roots" in an encounter with the Monster as a child.
While investigating his father's castle, Wolf ends up meeting Ygor, a demented blacksmith who has survived a hanging for graverobbing and has a deformed neck as a result. Wolf finds the Monster's comatose body in the crypt where his grandfather and father were buried with the chalk writing on his stone casket stating "Henrich von Frankenstein: Maker of Monsters."
He decides to revive it to prove his father was right and to restore honor to his family. Wolf starts out by using the torch to etch out the word "Monsters" on the casket and write "Men" in its place. When the Monster is revived, it only answers Ygor's wishes and commits a series of murders at his command; the victims were all jurors at Ygor's trial.
Wolf discovers this and confronts Ygor. Wolf ends up shooting Ygor, and apparently killing him. The Monster finds Ygor's body and abducts Peter as revenge. The Monster cannot bring himself to kill the child, however. When the abduction is discovered, Krogh and Wolf pursue the Monster to the nearby laboratory, where a struggle ensues, during which the Monster tears out Krogh's false arm.
Wolf swings on a rope and knocks the Monster into a molten sulphur pit under the laboratory, saving his son. The film ends with the village turning out to cheer the Frankenstein family as they leave by train. We also see Krogh has a new false arm. Wolf leaves the keys to Frankenstein's Castle to the villagers.
Basil Rathbone as Baron Wolf von Frankenstein
Boris Karloff as The Monster
Béla Lugosi as Ygor
Lionel Atwill as Inspector Krogh
Josephine Hutchinson as Elsa von Frankenstein
Donnie Dunagan as Peter von Frankenstein
Emma Dunn as Amelia
Edgar Norton as Benson
Perry Ivins as Fritz
Lawrence Grant as Burgomaster
Lionel Belmore as [Emil] Lang
Michael Mark as Ewald Neumüller
Caroline Frances Cooke as Mrs. Neumüller
Gustav von Seyffertitz as Burgher
Lorimer Johnston as Burgher
After the dissolve of the Laemmles with Universal and the British embargo on American horror films in 1936, Karloff and Lugosi found themselves in a career slump. For two years, horror films were out of the New Universal Studios line up. On April 5, 1938, a nearly bankrupt theatre in Los Angeles staged a desperate stunt by booking Frankenstein, Dracula and King Kong on a triple bill.
The result became a phenomenon, and soon Universal decided to make a big budget Frankenstein sequel. As director James Whale was similarly in a slump and did not wish to make any more horror films, Universal selected Rowland V. Lee to direct Son of Frankenstein. Lee's film explores dramatic themes: family, security, isolation, responsibility and father-son relationships.
Son of Frankenstein marks changes in the Monster's character from Bride of Frankenstein. The Monster is duller and no longer speaks. The monster also wore a giant fur vest, not seen in the first two Frankenstein films. He is fond of Ygor and obeys his orders.
Unlike the previous two films, the Monster only shows humanity in two scenes: first when he discovers Ygor's body, letting out a powerful scream and later when he contemplates killing Peter but changes his mind. Peter Lorre was originally cast as Baron Wolf von Frankenstein, but he had to leave the production when he became ill.
Replacing Lorre was Basil Rathbone, who had scored a major triumph as Sir Guy of Gisbourne in The Adventures of Robin Hood. According to the documentary Universal Horror (1998), the film was intended to be shot in color. Test shooting took place but the monster's make-up did not look good enough and the idea was abandoned. Color clips of Boris Karloff in monster make-up clowning around are included in the documentary.
The movie was a big hit and helped return Universal Studios to profitability. After the phenomenal success of Son of Frankenstein, Karloff decided not to return to the role of the monster, feeling that the monster was becoming the brunt of jokes.
Also Son of Frankenstein marked the final "A" production of Universal's Frankenstein films, which later went to "B" films, beginning with The Ghost of Frankenstein in 1942 in which Lon Chaney, Jr. took over the role of the Monster and Lugosi returned as Ygor.
Lugosi himself would go on to play the Monster in Frankenstein Meets the Wolf Man in 1943, while Karloff would return to the franchise as another character in 1944's House of Frankenstein. Karloff would not don the Monster makeup again for film until an episode of the TV series Route 66 in the 1960s.