Henry Frankenstein son's, Baron Wolf von Frankenstein, returns to his father's castle despite resentment of the villagers. Despite their haunting history with the Monster Frankenstein wants to continue his father's work with the help of the demented blacksmith, Ygor. Frankenstein and Ygor find and revive the body of the Monster however only disastrous horrors await for the young Frankenstein with the Monster only to be on the loose again controlled by the vengeful Ygor. This is the last of the Universal Frankenstein series that Boris Karloff play would play the Frankenstein Monster, however he would return in other roles.