A scientist made invisible by a new drug causes havoc in this adaptation of the novel by H. G. Wells.
A man whose face is wrapped with bandages enters an inn and asks for a room. Flora (Gloria Stuart) asks her father Dr. Cranley (Henry Travers) about Jack Griffin; he says he has been experimenting. After being a week late on the rent and breaking dishes when a servant disturbs him, she sends her husband to kick him out; but Jack Griffin (Claude Rains) throws him down the stairs. A constable comes in to arrest him; but he unwraps the bandages, revealing he is invisible. He says that he can rule the world. He throttles the constable, makes mischief, and rides off on a bicycle. Dr. Cranley tells his other assistant, Dr. Kemp (William Harrigan), of a drug that draws color but makes people mad. The unseen Griffin asks Kemp for bandages, clothes, and food, threatening to strangle him if he does not cooperate.
The inspector believes it is a hoax. Griffin tells Kemp how he did it and of the power he has; he asks Kemp to be his partner and suggests a few murders. They go in Kemp's car to get Griffin's books. Griffin goes in unseen, gathers the books, and then causes everyone to run out of the inn except the inspector, whom he strangles to death. Police ask everyone to help capture the invisible man. Kemp calls Dr. Cranley and tells him about Griffin; since he delays until morning, Kemp calls the police. Flora insists on going right away, and Griffin demands to talk with her alone. He tells her he did it for her, because he was poor. Griffin raves about power, and Flora says it changes him. Griffin sees the police arrive and tells Flora to go, saying he will come back after he has defeated them. The unseen Griffin tells Kemp he will kill him tomorrow night at ten. Griffin torments the police. Kemp asks the police for protection and tell them it is Griffin. Griffin derails a train and robs a bank.
The police plan a way for Kemp to escape and to paint Griffin; but Griffin accompanies Kemp in his car and sends him over a cliff. Griffin is noticed sleeping in a haystack. The police set the barn on fire, see his tracks in the snow, and shoot him in the lungs. While dying Griffin tells Flora he meddled in things that should be left alone.
This H. G. Wells parable shows how power can drive a man insane. Invisibility sets Griffin apart; unable to get back, he turns to mischief and crime to escape the repercussions of his actions, scheming how his discovery could create an invisible army to take over the world (foreseeing current stealth technologies). Yet the world united against him to stop his rampage of crime.