On a stormy night, Percy Bysshe Shelley (Douglas Walton) and Lord Byron (Gavin Gordon) praise Mary Shelley (Elsa Lanchester) for her story of Frankenstein and his Monster. Reminding them that her intention was to impart a moral lesson, Mary says she has more of the story to tell. The scene shifts to the end of the 1931 Frankenstein.
Shipwrecked traveler Edward Parker (Richard Arlen) is rescued by a freighter delivering animals to an isolated South Seas island owned by Dr. Moreau (Charles Laughton). When Parker objects to the freighter's captain (Stanley Fields) mistreating M'ling (Tetsu Komai), an odd-looking passenger, the captain tosses Parker overboard into Montgomery (Arthur Hohl) and Moreau's boat.
In a European village Henry Frankenstein, a young scientist, and his assistant Fritz, a hunchback, piece together a human body, the parts of which have been collected from various sources. Frankenstein desires to create human life through electrical devices which he has perfected.
Frankenstein, a young student, is seen bidding his sweetheart and father goodbye, as he is leaving home to enter a college in order to study the sciences. Shortly after his arrival at college he becomes absorbed in the mysteries of life and death to the extent of forgetting practically everything else. His great ambition is to create a human being, and finally one night his dream is realized. He is convinced that he has found a way to create a most perfect human being that the world has ever seen. We see his experiment commence and the development of it in a vat of chemicals from a skeletal being. To Frankenstein's horror, instead of creating a marvel of physical beauty and grace, there is unfolded before his eyes and before the audience an awful, ghastly, abhorrent monster. As he realizes what he has done Frankenstein rushes from the room as the monster moves through the doors Frankenstein has placed before the vat. The misshapen monster peers at Frankenstein through the curtains of his bed. He falls fainting to the floor, where he is found by his servant, who revives him.
I Was A Teenage Frankenstein's Roommate is the story of Hiram Belmore (Patrick Casey) and his attempt to create life and therefore win the school science fair. Peggy (Sarah K. Bizek) and her boyfriend Dwight (Nick Stukas) are house-sitting for Peggy's professor. Dwight's friend Hiram hijacks the house and uses it in his experiment to create his Frankenstein's monster, which he names Monster (Worm Miller). His class rival Lionel Kerr (Sean Hall) is trying to prevent this and win the science fair himself, while Clerval (Jack Shreck) co-opts control of a religious sect to make things turn out in his favor and wackiness ensues.