Synopsis by Hans J. Wollstein
An early science fiction-melodrama, advertised rather disingenuously as "the Greatest Serial the World Has Ever Seen," The Invisible Ray told the incredible tale of an unusual ray, discovered in Persia, whose power has a fatal effect on humans. The discoverer, a young mineralogist, secrets the ray in a sealed box made from lead, placing one key around the neck of his infant daughter while mailing the other to a colleague, Professor Stone. Years later, now a grown woman, Mystery (Ruth Clifford) is still wearing the key around her neck when she meets Jack Stone (Jack Sherrill), the son of Professor Stone and the possessor of the other key. Mystery is kidnapped by a gang calling itself the Crime Creators but manages to hold on to her key for the duration. Jack, meanwhile, is battling Haldane (Edwards Davis), a nasty specimen in league with the gang. Along the way, Mystery's long-lost mother, a crystal gazer known as Mariana (Corene Uzzell), turns up very much alive, and a cloaked mystery man, Jean Deaux (Sidney Bracey), proves to be the girl's father, long presumed to have become the ray's first victim. Enjoying some success on the low-budget states rights market in 1920, The Invisible Ray was co-directed (with the experienced Harry A. Pollard) by leading man Jack Sherrill, the son of the serial's executive producer, William L. Sherrill.