The first appearance and unveiling of the Monster - bringing him into the light of enlightenment - is truly memorable. The door slowly swings open, revealing a dark, lumpish silhouette in the doorway in a full figure shot. The bulky figure lurches clumsily into the room with halting steps, gradually revealing a bulky head and broad back - the Monster awkwardly moves into the room by backing in! The hulking Monster then slowly turns around, and then provides a shadowy profile in our first chilling close-up look of his blankly expressionless, tabula rasa face - a jagged surgical scar around the jaw appears. There is also a prominent spike that gleams into view on the side of the figure's neck. A series of camera jump cuts provide increasingly tighter close-ups of the hideous visage of the cadaverous creature.

The Frankenstein Monster (Boris Karloff) is a startling, grotesque, and gruesome figure, about seven feet tall with broad shoulders. The creation is more Monster than man. The monstrous face is placid, gaunt and elongated. The creature has a square-shaped head with boxy forehead, hooded eyelids over deep-set sunken eyes, neck-spikes or bolts to serve as electrical connectors on his neck, jagged surgical scars, and a matted wig. The Monster wears a dark suit and thick, heavy boots, causing him to walk with an awkward, stiff-legged, crude gait. His long arms seem enormous because the coat sleeves are shortened.

Frankenstein motions for the Monster to come in. As Henry moves backwards, the Monster leans forward at an angle, casting a towering, sinister black shadow over his creator. His bent posture causes him to not walk but fall forward - with each leg's step breaking his fall. Henry gestures for the Monster to sit down, and then exults when the Monster obeys him: "You see, it understands. Watch."

In a moving, symbolic sequence, when Henry opens the ceiling's skylight above him, the Monster sees sunlight for the first time and his face comes alive. With a child-like yearning for the unknown (and the beginnings of intelligence), he slowly rises, faces the light, and pleads and gropes heaven-ward - he stretches out his long, huge, open, corpse-like, scarred hands to try and reach up and grasp the golden shaft of sunshine coming through the skylight. Henry realizes that the effort is hopeless and fruitless and, at Waldman's persuasion, shuts out the intangible light from the window. Bewildered by the disappearance of the light, the Monster reacts piteously with confused frustration and wordless whimpers. He lowers his arms, and extends them in a beseeching and pleading gesture toward his Creator. Henry calms him and suggests: "Go and sit down." The Monster obliges and backs up - his face remains uplifted and his open hands still grasp for air, but the brightness of the light is shut out.

Frankenstein's Monster is frightened, panics and becomes violent when hunchbacked Fritz enters and brandishes a lighted torch. A struggle breaks out as the monster expresses fear of the flames - he utters lower gutteral cries and thrashes around. The three men attack and wrestle the troublesome Monster to the floor and overpower him. After subduing him, they tie him up with rope. "Shoot it. It's a Monster," Waldman shouts. The scene fades out, and as the next scene opens, the Monster is manacled to the wall and locked up in a downstairs dungeon cellar. The tormented Monster frantically utters more gutteral sounds as he struggles to break free of his restraining and binding chains.

The twisted dwarf Fritz takes cruel delight in teasing, intimidating, tormenting, and torturing the creature. The hunchback, who presumably hates the Monster because it reminds him of his own mis-shapenness, bullwhips the creature and waves a flaming torch in his face. Dr. Frankenstein is dismayed and haunted by his perverted creation and tells Fritz to quit mistreating the creature: "Oh come away, Fritz. Leave it alone. Leave it alone." He leaves the dungeon - abandoning his creation and feeling guilt for his complicity. Photographed from the point-of-view of the Monster, Fritz thrusts his flaming torch directly toward the camera to mercilessly torture the creature.

Later, Frankenstein and Dr. Waldman (up in the laboratory) hear terrible distress screams from Fritz. Provoked, the Monster breaks free from its chains and kills the hunchback (off-camera) when he gets too close, strangling him and impaling him on a hook from a rafter. By the time they reach the horrible scene in the cellar, they discover that the Monster has murdered Fritz. The violent Monster then turns on the two doctors - Frankenstein and Waldman. Waldman suggests overpowering the creature and injecting it with poison from a hypodermic needle to kill it: "as you would any savage animal...It's our only chance." In a violent confrontation, they lure the Monster out and inject him with a strong drug to render him unconscious. As the drug slowly starts to take effect, the creature loses its strength, looks quizzically around, and tries to comprehend what is happening. He collapses - successfully sedated and restrained. At that moment, Victor arrives at the door, announcing that Baron Frankenstein and Elizabeth are coming up the hill to see him. Frantically, the three men drag the creature's body into the cellar to hide it before Henry's father and Elizabeth arrive.

The Baron, who has come to take Henry away, first meets a shaken Victor and asks: "Well, what's the matter with you? You look as if you've been kicked by a horse. Where's Henry?" Dr. Waldman appears, introduces himself and then advises the Baron: "I would advise you to take Henry away from here at once." "What do you suppose I'm here for, pleasure?" the Baron responds.

Henry, originally proud of his creation, is now fearful of the horrible, uncontrollable creature he has produced, and he faints from the shock - close to a nervous breakdown. Waldman is told that the exhausted Frankenstein will be taken home with the Baron to get well. Nonetheless, Henry objects to being separated from his work: "No, I can't. My work. What will happen to the records of my experiments?" Waldman promises: "We will preserve them." While he is away, Waldman promises to see that the Monster will be "painlessly destroyed." Mentally and physically exhausted, Henry appears resigned to be taken home, very unhappy with the results of his experiments. He reluctantly abandons the Monster to Waldman.

Waldman resumes Henry's observations and prepares to perform a dissection upon the drugged-up Monster that is strapped to the table in the laboratory, with its right arm again hanging free. His journal notes that the Monster is becoming increasingly resistant to drugs: "Note increased resistance. Necessitating stronger and more frequent injections. However, will perform dissection at once." As the doctor listens to the Monster's heart beat before the operation, the Monster awakens, slowly raises his arm behind Waldman's back, grabs his neck, sits upright, and strangles him to death by breaking his neck. [To the Monster, Waldman represents another threat not unlike Fritz.] The scene dissolves away, showing the Monster, with giant powerful steps coming down the stairs from the laboratory. With short, jerky, hesitant movements, he passes the room where he killed Fritz and backs away. He stomps toward the main door, surprises himself when the door opens, and escapes from the tower into the outer world of his birth.

Henry begins to recover under Elizabeth's adoring care at Castle Frankenstein, away from his laboratory and his all-consuming experiments. (Henry assumes that Dr. Waldman has destroyed the Monster by this time.) He is at peace once again:

Henry: It's like heaven, being with you again.
Elizabeth: Heaven wasn't so far away all the time, you know.
Henry: I know, but I didn't realize it. My work. Those horrible days and nights. I couldn't think of anything else.
Elizabeth: Henry. You're not to think of those things anymore. You promised.

They make plans to marry soon. The village townspeople prepare to celebrate the marriage of Henry and Elizabeth. The Frankenstein family also prepares for the happy event - Baron Frankenstein raises a toast during the festivities: 'Here's to a very good health...to a son of the House of Frankenstein...Here's to jolly good health to Frankenstein." There is much dancing, drinking, and frivolity in the streets - a tracking shot follows dancing peasants through the streets.

In a similar tracking shot, the camera pursues the Monster as he haltingly roams through a forest in the countryside of the outside world. At his country home on the shore of a lake, a busy villager peasant named Ludwig (Michael Mark) leaves his young daughter Maria (Marilyn Harris) alone, telling her that after he returns from checking his traps, they will go to the village celebration.

In one of the film's most powerful, poignant, and horrifying scenes, the Monster parts the bushes and enters the clearing by the bank of the lake. He attempts to make friends with Maria who plays there by herself. [They share an affinity - her father also rejected her.] As she is gathering daisies at the edge of the water, she is not repelled by his hideous appearance or fearful of him and invites him to play and be her friend: "Who are you? I'm Maria. Will you play with me?" She takes his hand and leads him to the side of the lake. She asks: "Would you like one of my flowers?" and offers him one. A close-up of their two hands touching emphasizes the enormity of his hands. With child-like innocence, he smells the flower and a beatific smile lights his face. After they kneel next to the water, Maria hands him some flowers to join in her game of flinging them into the pond, and he compares his hand to hers: "You have those, and I'll have these. I can make a boat." One by one, they toss flowers onto the surface of the lake, watching the petals float. "See how mine float?" The Monster delights in the game with his new-found friend (his first) and is pleased when he throws a daisy and it floats.

When the Monster's few flower blossoms are gone, he puzzles for a moment at his empty hands, and then innocently and ignorantly picks up Maria. The little girl screams: "No, you're hurting me. No!" He enthusiastically throws her in the water - expecting that she, too, will float like the flower petals. She flounders and splashes in the water and quickly sinks and drowns. As he staggers away from the lake, the Monster seems to express some confusion, despair and remorse - shaking and wringing his hands and possibly perceiving the horrible thing he has done. [In the original version of the film, the scene was truncated and it cut away from the drowning - it was considered too gruesome and cruel to remain. However, the excision implied some other kind of undesirable, unseen fate for the girl beyond a drowning. The drowning scene wasn't restored to the film until the mid 1980s.]

Dressed in her beautiful wedding gown with a long train on their wedding day, a tense, worried, and uneasy Elizabeth asks to speak to Henry in private before they are married - she has a premonition of danger:

Elizabeth: Henry. I'm afraid. Terribly afraid. Where's Dr. Waldman? Why is he late for the wedding?
Henry: (assuring her) Oh, he's always late. He'll be here soon.
Elizabeth: Something is going to happen. I feel it. I can't get it out of my mind.
Henry: You're just nervous. All the excitement and preparation.
Elizabeth: No, no. It isn't that. I felt it all day. Something is coming between us. I know it! I know it!
Henry: Sit down and rest. You look so tired.
Elizabeth: If I could just do something to save us from it.
Henry: From what, dear, from what?
Elizabeth: I don't know. If I could just get it out of my mind. Oh, I'd die if I had to lose you now, Henry.
Henry: Lose me? Why, I'll always be with you.
Elizabeth: Will you, Henry? Are you sure? I love you so.

Elizabeth's worries prove to be warranted. Just then, Victor interrupts them with frantic knocking on the door: "Henry! Dr. Waldman!" A close-up shows Frankenstein locking his bride's chamber door before Victor delivers news of the murder of Dr. Waldman in the tower - and the Monster's escape: "He's been seen in the hills terrorizing the mountainside." Henry hears a low moan and recognizes the Monster's distinctive voice: "He's in the house. He's upstairs!" While checking upstairs rooms and the cellars, the Monster enters a window of the Frankenstein mansion into the room where Elizabeth is seated - alone and helpless. She is horrified by his appearance and screams loudly. The Monster is driven off by the screams and by Frankenstein and his servants who rush to her aid. She swoons and is quite shaken and dazed by the incident, but unhurt.

After the dead body of the drowned little girl is discovered, the girl's father carries her in his arms through the streets of the celebrating village to the door of the burgomaster Herr Vogel. The celebrations in the village come to a sudden halt as the revelers follow behind him. He explains: "Maria, she's drowned...She has been murdered." Herr Vogel promises revenge for the murder: "I'll see that justice is done. Who is it?" The townspeople are driven by fear, indignation and hate to hunt down the creature and destroy the outcast.

The wedding will have to be postponed for at least a day. Resolved to reject his creation, Frankenstein thinks the wedding may have to be postponed longer: "A day? I wonder...There can be no wedding while this horrible creation of mine is still alive." Dr. Frankenstein vows to destroy the fiendish Monster:

I made him with these hands, and with these hands I will destroy him. I must find him.

Firmly looking into Victor's eyes in a close-up, he entrusts his fiancee into Victor's care while he goes to pursue his Monster himself: "You stay here and look after Elizabeth. I leave her in your care, whatever happens. Do you understand? In your care." As the scene ends, Victor turns toward Elizabeth's bedroom.

In a climactic pursuit scene, Frankenstein joins a large search party of peasants commissioned by the burgomaster to take up glowing torches, pitchforks, and bloodhounds and set off after the murderous monster, chasing it through the dark night. They are split into three torch-bearing groups to search for the creature - into the woods, the craggy mountains, and by the lake. They are commissioned to "get him alive if you can, but get him...Search every ravine, every crevice...The Fiend must be found." Henry leads one group into the mountains but becomes separated from his search group.

He finds himself reunited and face to face confronting his hideous, angry creation on a rocky, hilltop outcropping. In a violent struggle, Henry is beaten, choked, knocked out, and then dragged to an old, abandoned windmill. The torch-bearing villagers hear Henry's cries, pursue them, and turn their dogs loose. They surround the mill but are unable to break down the mill's door which has been blocked by a fallen rafter.

The Monster snarls at the enraged villagers and then drags Dr. Frankenstein into the upstairs room of the mill. Dr. Frankenstein regains consciousness and another life and death struggle and confrontation ensue as they stalk each other around a rotating, slatted wheel. The Monster and his creator further battle each other on the top balcony ledge of the windmill - the Monster seizes Henry before he can climb down. He lifts and throws Henry's body to the ground below - but he is saved when a turning windmill blade arm breaks his fall. The windmill vane supports him for a short distance, and then drops him to the ground. Henry is severely injured and hurt, but still alive. The villagers cry out: "Burn the mill! Burn it down! Burn the mill!" They set the structure, where the Monster is trapped inside, on fire.

Amid the crackling of flames, the poor, tragic Monster waves his arms and runs around in a panic, letting out frightened, high-pitched, quavering cries - tormented by fire one more time. He is crushed by a falling beam in the mill tower and pinned down, apparently perishing in the blazing fire and the collapsing, incinerated structure. After the scene of mob violence, the villagers carry Dr. Frankenstein's limp, critically-injured body home, as the windmill goes up in flames. A long-shot of the burning mill (with its revolving windmill) resembles a burning cross.

[Originally, the film ended here, but the unhappy denouement displeased preview audiences, so a short epilogue was added. The film concludes with a requisite happy ending, although the symbolism of the transgressing Creator killed by his deformed, monstrous creation - as sensed by Elizabeth - might have been more appropriate.]

At his home, Frankenstein (still unwed) recovers from his injuries with Elizabeth at his side and nursing him back to health. The maids bring a drink tray to Henry's room, but the Baron intercepts the wine. Standing outside his son's sick-room in the hallway, he pours a drink for himself with a toast:

As I said before, I say again, 'Here's, here's to a son, to the House of Frankenstein.'

The maids respond: "Indeed, sir. We hope so, sir."