Late one night, Doctor Frankenstein, along with his hunchback assistant Fritz, steal a large hulking body from the gallows. The body is repaired and a brain is placed in (unknown to Frankenstein, Fritz had accidentally destroyed the perfect brain and so the damaged one was put in instead). The creature is then brought to life when it is raised to the top of Frankenstein's castle and struck with lightning.
The creature wanders around the castle aimlessly exploring until it comes to an open ceiling were it admiers the light, watched by Frankenstein and his friend Dr. Waldman but Fritz arrives with a burning torch which scares the monster. It reacts, but Frankenstein mistakes this for aggression and places it in the dungeon.
In the dungeon Fritz starts to torment the creature with flames and whipping it, much to the disproval of Frankenstein. Eventually the creature snaps and hangs Fritz from the ceiling with his own whip hung around his neck. The two doctors rush in to find Fritz's body hanging from the roof. They find the monster and drug it so it falls asleep.
Frankenstein prepares to leave for his wedding with his fiancee Elizabeth. At the same time Dr. Waldman prepares to operate on the creature so he can remove its brain, but the drug wears off and the creature awakens and kills Waldman. It escapes and wanders until it comes across a little farm girl named Maria. The girl asks to play with the creature and she throws daisy's onto the water. The monster has a go but runs out of daisys so he picks up the girl and throws her in instead. Maria drowns and the creature realises what has happend and flees. (this scene was originally cut for being to shocking, but this was the main scene were the creature shows compassion and love.)
After the wedding the newly wed couple arrive at the castle. Elizabeth goes upstairs and Frankenstein goes to find Waldman only to find his body. He then hears a scream and finds his wife who had fainted and the window wide open.
The girl's father finds Maria and carry's her body through the town and a mob ensures. They start to hunt the monster with Frankenstein in the lead. They successfully chases it to the mountains, but the beast captures Frankenstein and carries him to an old abandoned windmill, the mob follows. Angrily the Monster throws Frankenstein from the top of the windmill and into the crowd. They rush the doctor back to his home were he later recovers. The mob sets the fire to the windmill killing the creature. Or did it?