Professor Grant signs a contract with Dr. Selin for the sale of his invention of cold light with the plans for his invention being kept in Grant's apartment. The negotiations are secretly heard by the illusionist Durk, who wants to seize the invention. A few days later Selín is found dead, killed by a light bulb filled with poisonous gas. Durk performs at the birthday party of Grant's daughter Anna and seizes the plans for the invention.
Professor Oskar Grant
Anny Grant
Ing. Milan Bell
Dr. Karel Selín
Durk, the Magician
Ferdinand Kardan
Martin Bálek
Baron Evans Margus / Servant
Jan
President of Police
Hynek, reporter
Grant's Assistant
Hall
Selín's Companion
Gatekeeper
Seance Guest
Seance Guest