The Invisible Ray is a 1920 American science fiction film serial directed by Harry A. Pollard.

Plot

After a mineralogist discovers a ray with extraordinary powers, a group of scientists seek to use it for a criminal scheme. The serial begins, as described in a film magazine, with the two keys to a box that contains the source of the rays which, if concentrated, are powerful enough to destroy the world. One of the keys is hung around the neck of Mystery (Clifford), a foundling girl who is the daughter of the mineralogist. The second key and the box are in unknown hands at the beginning of the serial. Jack Stone (Sherrill) loves her, but on the night of their planned elopement Mystery is kidnapped for the key she wears, which falls at the door of the minister. She is taken to an underground chamber where she is tortured in an attempt to force her to give up her key. Jack and a friend visit a Crystal Gazer who reveals the whereabouts of Mystery. In a thrilling chase through underground chambers the young woman is rescued, only then to fall back into the hands of her enemies. Mystery is swung from a derrick and falls into the water. Later serial chapters reveal Marianna, the Crystal Gazer (Uzzell), as the mother of Mystery, and her father turns out to be her pursuer, attempting to gain possession of the box and its key.