- Directors: James Whale
- Producers: Carl Laemmle Jr
- Writers: Novel, H G Wells, Screenplay, R C Sherriff, Uncredited, Philip Wylie, Preston Sturges
- Genres: Horror, Sci-Fi, Thriller
- Actors: Claude Rains, Gloria Stuart
The film opens with a mysterious stranger, his face swathed in bandages and his eyes obscured by dark spectacles, taking a room at an inn at the English village of Iping (in Sussex). Never leaving his quarters, the stranger demands that the staff leave him completely alone. However, his dark secret is slowly revealed to his suspicious landlady and the villagers: he is an invisible man. When the innkeeper (Forrester Harvey) and his semi-hysterical wife (Una O’Connor) tell him to leave after he makes a huge mess in the parlor and drives away the other patrons, he tears off the bandages, laughing maniacally, and throws the innkeeper down the stairs. He takes off the rest of his clothes, rendering himself completely invisible, and tries to strangle a police officer.
The invisible stranger is revealed as Dr. Jack Griffin (Claude Rains), a scientist who has discovered the secret of invisibility while conducting a series of tests with a strange new drug called “monocane”. He returns to the laboratory of his mentor, Dr. Cranley (Henry Travers), where he reveals his secret to his fiancee Flora Cranley (Gloria Stuart), Dr. Cranley’s daughter, and to his one-time partner Dr. Kemp (William Harrigan). Monocane has rendered Griffin’s entire body undetectable to the human eye; alas, it also has the side-effect of driving Griffin insane. Cranley has investigated and discovered a single note about monocane (Griffin has burnt all his other papers to cover his tracks) in a now empty cupboard in Griffin’s empty laboratory, and realizes that Griffin has recently used it. On the evening of his escape from the inn, Griffin turns up in Kemp’s living room and imprisons him in his own house. He forces Kemp to be his partner again, and together they go back to the inn where Griffin stayed and retrieve his notebooks on the invisibility process. While there, he picks up a wooden stool and cracks the police officer over the head, killing him.
Although the film is sometimes hailed for its fidelity to H.G. Wells’ novel, it changes many aspects. The story is updated to 1933, rather than taking place in the 1890s. Griffin does not have a fiancee in the novel, there is no Dr. Cranley, and Griffin does not kill Kemp. (In fact, in the book, it is Kemp who pronounces Griffin dead at the end.) Kemp is neither an old friend nor an old partner of Griffin’s in the novel, just an acquaintance. Most important, Griffin does not use monocane to make himself invisible in the book, but instead another unnamed formula, and it is strongly hinted in the novel that Griffin was already mad long before he ever made himself invisible. The film portrays Griffin much more sympathetically than the novel, in which Kemp describes Griffin as “inhuman” to the police. In the film, he is shown regretting what he has done to Flora; Griffin shows no such regrets in the novel.