The scientist's son is a doctor and revives the monster, who is controlled by a hanged man.
Town officials fear the arrival of Frankenstein's son Wolf. On the train Baron Wolf von Frankenstein (Basil Rathbone) tells his wife Elsa (Josephine Hutchinson) that his father was right. The burgomaster gives Wolf his father's papers; but when Wolf speaks, the villagers walk away. Wolf, Elsa, and their son Peter (Donnie Dunagan) are welcomed by their servants Benson (Edgar Norton) and Amelia (Emma Dunn). Inspector Krogh (Lionel (Atwill) calls on Wolf to offer him protection. Krogh says the Monster tore off his arm, and six murders are unsolved. Wolf goes to his father's laboratory. Ygor (Bela Lugosi) tries to kill Wolf with a boulder. Ygor says he was hanged for stealing bodies, and he shows Wolf tombs and the Monster (Boris Karloff), asking Wolf to heal him. The council tells Krogh to bring in Ygor. Wolf tells Ygor he must have Benson's help; he examines the Monster and says he is superhuman. Ygor is questioned by the council and warned. Wolf uses a generator to revitalize the Monster but gives up.
The servant Fritz (Perry Ivins) tells Krogh he is quitting, but Krogh hires him to spy. Elsa tells Krogh that Wolf is experimenting. Wolf and Krogh talk. Peter comes in and says a giant woke him up. Wolf looks in the lab and calls for Ygor. The Monster walks in and put his hands on Wolf. Ygor comes in and says Wolf made him well. Wolf says he must cure the Monster's mind, but Ygor tells Wolf not to touch him. Wolf tells Benson it is alive and says Elsa and Peter must go away. Ygor points out a tradesman to the Monster, who kills him. Krogh dines with Wolf and Elsa, who asks Fritz where Benson is. Krogh is told of a death and leaves. Ygor tells Wolf that Benson ran away from the Monster. Dr. Berger tells Krogh that the man was killed by his wagon. Elsa tells Wolf she is afraid and brings Peter to her bed. The Monster hits the apothecary. A bell draws a crowd.
Krogh asks Wolf about Benson and says his family cannot leave. As a mob arrives, Krogh tells Elsa he will protect them. Peter shows Krogh Benson's watch the Monster gave him. Elsa tells Wolf she suspects him. Krogh leaves, and Wolf goes to the lab. Ygor stops Wolf from crushing the Monster. Ygor says all eight men who condemned him are now dead. Krogh returns to tell Wolf of the apothecary's death. People say the Monster did it, and Krogh arrests Wolf for the murder of Benson. Wolf says it was Ygor, but Krogh says Igor has an alibi. Wolf finds Ygor and shoots him. Krogh gets the door open and finds Benson dead. The Monster discovers Ygor is dead. Wolf tells Krogh that he killed Ygor in self-defense. Krogh asks where the Monster is. The angry Monster destroys lab equipment and puts down Amelia in order to take Peter with him. Krogh shoots the Monster, and Wolf pushes him into the boiling sulfur. In the final scene Wolf deeds the castle to the town and says good-bye.
This sequel to Mary Shelley's story finds another generation
experimenting on prolonging life; but a convicted criminal wreaks
havoc getting revenge on his jury.