Daniel Mendaille is a mocked by the scientific establishment for his researches into harnessing the power of natural lightning. What makes it worse is that he, and three other relatives are all in love with Jane Maguenat; they have all proposed marriage, and the time has come for her to give her answer. She explains her father is ruined; in three months the creditors will take everything. Therefore she proposes to marry whichever of the four will bring her a fortune to save them. Mendaille despairs, but wandering by a waterfall near Mlle Maguenat's home, he meets a mysterious stranger, while confides he has built a plant nearby that uses the power from the waterfall. When Mendaille explains his ideas, the stranger offers to back him.
Soon the audience sees a test of the apparatus. Using the power from the water, clouds arise on a clear day, and lightning strikes a forest. Shortly thereafter, Paris receives a message: pay fifty million francs or an entire neighborhood will be destroyed. There is general laughter, but....
This is what science fiction in the movies was like in this era, something that combines immense power with the "evil genius" motif. It was easily mocked, and the same year, Rene Clair directed PARIS QUI DORT with a similar theme. This movie is quite watchable, with many scenes of destruction (including the Eiffel Tower) and good editing, although the ending is a bit of a letdown.
Review by boblipton from the Internet Movie Database.