On a dark and stormy night in Transylvania, on the hundredth anniversary of the birth of Baron Beaufort von Frankenstein and fifteen years after his death, the box containing his will is removed from his casket and read. Not long after, in Baltimore, the Baron’s great-grandson Frederick, a pre-imminent brain surgeon who insists that his surname is “Fronkensteen,” learns that he has inherited Beaufort’s estate. Despite his desire to distance himself from the notorious legacy of his deceased grandfather Victor, who animated stolen corpses, Frederick temporarily takes leave of his fussy fiancée Elizabeth to go to Transylvania. At the train station there, Igor, a hunchback who pronounces his name “Eye-gor” introduces him to Inga, a buxom blonde lab assistant and, at the candlelit Frankenstein castle, Frederick meets its fearsome housekeeper, Frau Blücher, whose very name frightens horses. During the night, the haunting strain of a tune played on a violin lures Frederick to investigate its source, and he discovers a secret passage that leads to Victor’s laboratory. In Victor’s private library off the lab, Frederick finds the violin, still warm from being played, and a book by Victor, entitled How I Did It , that inspires him to recreate Victor’s experiments. The next day at breakfast, when Frederick says he will need a corpse with a very large brain, Inga makes the point that the other organs would also be large. After Igor informs Frederick that a huge man is being hanged that day, the following night, they dig up the corpse. Frederick then sends Igor to a brain depository to steal a brain that formerly belonged to an intelligent and good-hearted man. However, during the theft, Igor accidentally damages that brain and instead takes one that is marked “abnormal.” Unaware of the switch, Frederick surgically fits the stolen brain into the corpse. With Igor and Inga’s help, the corpse is wired to Victor’s equipment and to flying kites being used to harness the electrical power of lightning. During a thunderstorm, Frederick has Igor turn on the machines and hopes that an electrical charge will spark life into his creation, but despite the flashing and buzzing, nothing happens. Frederick is despondent, believing that the experiment failed, until the corpse later comes to life. When the monster, who shows a tendency to violence when frightened, almost strangles Frederick after Igor lights a match, Igor admits that he took the brain of someone named “Abbie Normal.” Meanwhile, at a town meeting, the villagers are concerned about having another Frankenstein scientist in the neighborhood, as some of them still suffer injuries from the monster Victor created. Police Inspector Kemp, despite having lost an arm fighting Victor’s monster, attempts to calm the crowd by offering to talk to Frederick about his intention of repeating his grandfather’s work. Later, when Kemp arrives, Frederick has just become aware of the danger he has created and guiltily conceals the presence of the sedated monster locked up in the laboratory. Kemp then returns to the villagers planning to allay their fears. Afterward, Frederick discovers that Frau Blücher has released the monster and shows Frederick that his creation, like Victor’s monster, can be calmed by playing the haunting violin tune. Revealing that Victor was her "boyfriend," Frau Blücher admits that she played the tune that prompted Frederick to find the laboratory, because she wants his work to be continued. As they talk, the monster stumbles against electrical equipment, causing sparks that panic him and send him floundering out the castle. Some time later, the monster encounters Helga, a little child who does not fear him, then is beguiled by the music of a gramophone at the hut of a blind hermit. Eager for company and mistaking the monster’s moaning sounds for muteness, the hermit shares his meal, oblivious that he ladles hot soup into his guest’s lap and smashes the wine out of the monster’s hand while making a toast. When the blind man offers a cigar, he inadvertently sets the monster’s thumb on fire, causing him to leave, roaring in pain. By playing the violin, Frederick lures the monster to him, while Inga and Igor capture him in a net and inject him with a sedative before returning him to the castle. Believing that love will help the monster, Frederick risks his life to embrace him, then speaks tenderly to him, until the creature weeps in his arms. Frederick then educates the monster and later presents him to the Bucharest Academy of Science. During a demonstration, Frederick shows that the monster is a “cultured, sophisticated man about town” by performing the song, “Puttin’ on the Ritz,” with both wearing top hat and tails. Although the audience applauds enthusiastically, the success is short-lived when the monster becomes agitated by the pop of a stage light that he accidentally bursts. The audience then boos its disapproval and throws food, further panicking the monster, who knocks down Frederick and lunges at a policeman. As the audience flees, the monster is apprehended. Later, while the monster sits forlorn in a dank prison cell bound by several chains, Frederick searches for a way to equalize the imbalance of the his spinal fluid, which, he believes, will make his creation normal. Frederick also finds solace with Inga, who relieves his tension with sex. Immediately afterward he receives a cable from Elizabeth, announcing her arrival seconds later. Meanwhile, at the prison, a sadistic jailor torments the monster with lighted matches until the desperate creature breaks his chains and escapes. Everyone is concerned about the monster being loose, except the practical Elizabeth. After insisting that she and Frederick remain chaste until their wedding night, she is alone preparing for bed, when the monster enters through the window and carries her off to a cave. Lustful, he initiates sex and Elizabeth experiences such pleasure that she falls in love with him and sings, “Ah, sweet mystery of life.” After more sex, she feels abandoned when the monster is lured away abruptly by the sound of a violin. The music, emanating from high up in the castle, is being played by Frederick, amplified by a megaphone and accompanied by Igor on French horn. After the monster struggles up the side of the castle wall toward the music, Frederick instructs Inga and Igor to strap the monster and himself to two separate platforms and hook their brains together with wires. After explaining the importance of having the electrical current constant between them for exactly fifteen minutes, Frederick orders that the procedure commence. During the last two minutes, the rioting villagers led by Kemp break down the castle door using Kemp’s false arm. Despite Inga and Igor’s plea to wait three more seconds, they break the electrical connection and attempt to lynch Frederick. However, the monster, now able to talk, orders them to stop. Then he eloquently explains that people’s hate created his desire to inspire fear, rather than his natural inclination, love. He talks affectionately about Frederick, who considered him beautiful and risked his life to give him a calmer brain. Acknowledging that the situation has changed, Kemp offers his hand in friendship, then invites everyone to his cottage for sponge cake and wine. Some time later, Elizabeth, who is living in happy domesticity with the now civilized monster, eagerly seduces him into laying aside his Wall Street Journal . Frederick and Inga also marry, and on their wedding night Inga discovers that in exchange for part of Frederick’s brain, Frederick received something substantial from the monster. She begins singing, “Ah, Sweet Mystery of Life,” while, on the castle balcony, Igor plays the French horn.