Boris Karloff stars in the role that made him a screen legend in this, the second sequel to the famous horror classic. The son of Dr. Frankenstein returns to the ancestral gamily castle 25 years after the explosive death of the monster. There he meets Ygor a mad shepherd who is hiding the comatose body of the creature. Hoping to clear the family name, the young Dr. Frankenstein revives the creature and attempts to rehabilitate him. But his noble goals are circumvented when Ygor send the creature on a killing spree that spreads a new panic in the village.