The trailer for The Ghost of Frankenstein.
Picking up after the events of Son of Frankenstein, Ghost sees the Monster brought back to life with some help from the insane Ygor (again played by Lugosi). Ygor is forced to turn to a second son of Dr. Henry Frankenstein, Ludwig (Sir Cedric Hardwicke), in order to keep the Monster alive. When the doctor determines to replace the Monster's original criminal brain with that of a benevolent, murdered colleague, Ygor conspires to have his own brain implanted into the Monster instead; however, although the Monster is resurrected with Ygor's mind and can even speak with his voice, a complication in the procedure renders the creature blind, and he is unable in the film's finale to find his way out of the burning Frankenstein mansion.